Membrane Roofing
Neutrality remake campaign: from-scratch field derivation per authoring cheatsheet; project parameters and derived dispositions
Showing changes from Rev 6
to Rev 7
in Membrane Roofing.
−---
−title: Membrane Roofing
−category: Building Envelope
−toc_depth: 3
−description: >
− When to use: Single-ply low-slope membrane roofing systems using thermoplastic polyolefin (TPO), polyvinyl chloride (PVC), or ethylene propylene diene monomer (EPDM) membranes on new construction and roof replacement projects with roof slopes of 1/4:12 or greater and not exceeding 3:12. Covers mechanically attached, fully adhered, and ballasted attachment methods, polyisocyanurate and cover-board insulation, vapor retarder, all flashings and terminations, edge metal, wind-uplift and fire design, field testing, and manufacturer warranty requirements.
− Not intended for: Below-grade or foundation waterproofing ([[sync/below-grade-waterproofing]]); steep-slope applications exceeding 3:12 (use tile, shingle, or standing-seam metal standards); liquid-applied or spray polyurethane foam roofing; vegetative (green) roof assemblies; modified-bitumen or built-up roof systems; thermal insulation design for above-grade walls ([[sync/building-thermal-insulation]]); architectural sheet metal flashings and copings beyond the scope of this standard ([[sync/sheet-metal-flashing-and-trim]]).
−---
−
−# Scope {toc}
−
−## This standard covers the materials, design basis, installation, testing, and warranty requirements for single-ply low-slope membrane roof systems on commercial, institutional, and industrial buildings. {note}
−## The three membrane technologies addressed — thermoplastic polyolefin (TPO), polyvinyl chloride (PVC), and ethylene propylene diene monomer (EPDM) — collectively represent the dominant choices in the low-slope roofing market and share a common design and installation logic even though their chemical composition and seaming methods differ. {note}
−## Governing this standard as a unified document promotes consistent detailing, submittal practice, and quality-assurance rigor across all three technologies rather than treating each as a wholly separate scope. {note}
−
−## System Basis {toc}
−
−### The membrane, insulation, cover board, vapor retarder, fasteners, flashings, edge metal, and accessories function together as an integrated assembly whose performance — thermal, wind-uplift, fire, and waterproofing — depends on the compatibility and correct installation of every component. {note}
−### A membrane that meets its material standard but is installed over incompatible insulation, fastened at the wrong spacing, or terminated with undersized edge metal can fail despite the quality of its constituent parts. {note}
−
−### Low-slope membrane roofing is a building-envelope system, not merely a waterproofing layer. {note}
−
−### The entire roofing assembly shall be designed and installed as a system, with every component selected from an FM-approved or UL-classified assembly that has been tested as a unit.
−
−## Applicable Slopes {toc}
−
−### The maximum 3:12 limit reflects the practical performance ceiling for ballasted systems and the increased tendency for fully adhered membranes to slip on steeper substrates; slopes above 3:12 require a different roofing technology. {note}
−### Ponded water accelerates membrane degradation, imposes sustained structural loads not included in typical roof-deck design, and constitutes a code violation under IBC Section 1503.4. {note}
−
−### Applicable roof slopes are 1/4:12 (approximately 2% or 1/4 inch per foot) through 3:12.
−
−### Where the deck slope is below 1/4:12, the roof shall be redesigned with tapered insulation or crickets to achieve positive drainage.
−
−### Single-ply membrane shall not be installed on a net-zero slope deck.
−
−## Contractor Certification {toc}
−
−### The membrane manufacturer requires an approved contractor status as a precondition for issuance of a No Dollar Limit (NDL) warranty. {note}
−
−### The Contractor shall hold a current, manufacturer-issued certification or qualification for the membrane system being installed prior to commencing work.
−
−### This certification requirement is not waivable and applies regardless of the Contractor's general roofing experience. {note}
−
−# Referenced Standards {toc}
−
−## All materials, design, and installation shall conform to the latest adopted edition of the following standards unless a specific edition is cited as the controlling document by the Authority Having Jurisdiction or the Owner's insurance carrier.
−## Where conflict exists between standards, the more stringent requirement governs unless the Engineer of Record directs otherwise in writing. {note}
−
−| Standard | Title |
−|----------|-------|
−| ASTM D6878/D6878M | Standard Specification for Thermoplastic Polyolefin-Based Sheet Roofing |
−| ASTM D4434/D4434M | Standard Specification for Poly(Vinyl Chloride) Sheet Roofing |
−| ASTM D4637/D4637M | Standard Specification for EPDM Sheet Used in Single-Ply Roof Membrane |
−| ASTM C1289 | Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board |
−| ASTM C1177 | Standard Specification for Glass Mat Gypsum Substrate for Use as Sheathing |
−| ASTM C728 | Standard Specification for Perlite Thermal Insulation Board |
−| ASTM E108 | Standard Test Methods for Fire Tests of Roof Coverings |
−| UL 790 | Standard Test Methods for Fire Tests of Roof Coverings (equivalent to ASTM E108) |
−| ASTM D1970 | Standard Specification for Self-Adhering Polymer Modified Bituminous Sheet Materials Used as Steep Roofing Underlayment for Ice Dam Protection |
−| FM Global Data Sheet 1-28 | Wind Design |
−| FM Global Data Sheet 1-29 | Roof Deck Securement and Above-Deck Roof Components |
−| FM 4470 | Standard for Class 1 and Class 1 Noncombustible Construction — Roofing |
−| FM 4474 | American National Standard for Evaluation of Simulated Wind Uplift Resistance of Roof Assemblies Using Static Positive and/or Negative Differential Pressures |
−| ANSI/SPRI/FM 4435/ES-1 | Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems |
−| ASCE 7 | Minimum Design Loads and Associated Criteria for Buildings and Other Structures |
−| NRCA Roofing Manual | Low-Slope Membrane Roof Systems |
−| IBC | International Building Code — Chapter 15 (Roof Assemblies and Rooftop Structures) |
−| ASHRAE 90.1 | Energy Standard for Buildings Except Low-Rise Residential Buildings |
−| SMACNA Architectural Sheet Metal Manual | Current Edition |
−
−# Submittals {toc}
−
−## Action Submittals {toc}
−
−### Contractor shall submit the following for review and approval before procuring materials or beginning installation.
−### The membrane, insulation, and edge-metal submittals are interdependent; they shall be submitted together as a single package so that the assembly can be verified as a listed, tested system rather than reviewed component by component.
−
−- Product data sheets for the membrane (TPO, PVC, or EPDM), confirming ASTM compliance, nominal and minimum thickness, reinforcement type, tensile and seam strength, and applicable FM approval number and UL classification
−- Product data sheets for all insulation layers, cover board, and vapor retarder, including FM-approved assembly numbers for which those products are a component
−- Product data sheets for membrane adhesive, seam primer, seam tape (EPDM), field-applied lap sealant, and all accessory items (pipe boots, walkway pads, termination bar, pitch pockets, cants)
−- Current FM RoofNav assembly listing confirmation for the complete as-specified assembly, including deck type, insulation type and thickness, cover board, attachment method, and fastener pattern, confirming the wind-uplift rating equals or exceeds the design requirement
−- UL fire-classification listing confirmation for the complete assembly on the specified deck type
−- ANSI/SPRI ES-1 test reports for all perimeter edge metal and coping cap systems, confirming the tested wind pressure meets or exceeds the design edge-zone pressure from ASCE 7
−- Shop drawings for all perimeter edge metal, coping caps, and scuppers, showing dimensions, gauges, joinery, and expansion joint locations
−- Contractor's current manufacturer authorization or certification certificate
−- Manufacturer's standard warranty form and any supplemental requirements for NDL warranty eligibility
−
−```datasheet
−label: Action Submittals Required
−type: checkbox
−options:
− - Membrane product data (ASTM compliance, thickness, FM/UL listing)
− - Insulation, cover board, and vapor retarder product data
− - Adhesive, primer, seam tape, lap sealant, and accessory product data
− - FM RoofNav assembly listing confirmation
− - UL fire-classification listing confirmation
− - ANSI/SPRI ES-1 test reports for edge metal and coping
− - Shop drawings for edge metal, coping caps, and scuppers
− - Contractor manufacturer authorization certificate
− - Manufacturer warranty form and NDL eligibility requirements
−default:
− - "Membrane product data (ASTM compliance, thickness, FM/UL listing)"
− - "Insulation, cover board, and vapor retarder product data"
− - "FM RoofNav assembly listing confirmation"
− - "UL fire-classification listing confirmation"
− - "ANSI/SPRI ES-1 test reports for edge metal and coping"
−```
−
−```datasheet
−label: Membrane Type
−type: radio
−options:
− - "TPO (thermoplastic polyolefin) — ASTM D6878"
− - "PVC (polyvinyl chloride) — ASTM D4434"
− - "EPDM (ethylene propylene diene monomer) — ASTM D4637"
−default: "TPO (thermoplastic polyolefin) — ASTM D6878"
−```
−
−## Closeout Submittals {toc}
−
−### Contractor shall provide the following at substantial completion before the roofing system is accepted and before the membrane warranty is issued.
−
−- Manufacturer's warranty, executed and dated, covering the complete roofing assembly for the specified warranty term
−- Contractor's installation warranty
−- Manufacturer's pre-warranty inspection report, if required by the manufacturer as a condition of warranty issuance
−- Field test reports for all flood tests, core cuts, and electronic leak detection surveys performed during or after installation
−- As-installed drawings showing the layout of membrane panels, seam locations, drain locations, and locations of all penetrations and curbs
−- Material certifications confirming that all membrane rolls and insulation boards used on the project conform to the specified ASTM standards
−
−```datasheet
−label: Required Closeout Submittals
−type: checkbox
−options:
− - Manufacturer's executed and dated warranty
− - Contractor's installation warranty
− - Manufacturer pre-warranty inspection report (if required)
− - Field test reports (flood test, core cuts, ELD)
− - As-installed drawings (panels, seams, drains, penetrations, curbs)
− - Material certifications confirming ASTM conformance
−default:
− - "Manufacturer's executed and dated warranty"
− - "Contractor's installation warranty"
− - "Field test reports (flood test, core cuts, ELD)"
− - "As-installed drawings (panels, seams, drains, penetrations, curbs)"
− - "Material certifications confirming ASTM conformance"
−```
−
−# Quality Assurance {toc}
−
−## Contractor Qualifications {toc}
−
−### Manufacturer authorization is typically renewed annually and requires demonstrated completion of manufacturer-sponsored training and a minimum volume of satisfactory installations. {note}
−
−### The Contractor shall be an authorized, trained installer, certified or approved by the membrane manufacturer for the system being installed.
−
−### The Contractor shall submit evidence of current authorization before the submittal package is approved.
−
−### The use of an unauthorized installer voids any manufacturer warranty and is cause for rejection of the work. {note}
−
−### The roofing foreman assigned to this project shall have a minimum of five years of documented field experience with the membrane type being installed.
−
−### Where hot-air welding of thermoplastic membranes is required, the welding operator(s) shall be trained on the specific hot-air welder model being used and shall demonstrate proficiency by producing acceptable test welds before production welding begins.
−
−## Pre-Installation Conference {toc}
−
−### A pre-installation conference shall be held before the start of roofing work, attended by the Contractor, the Contractor's roofing foreman, the membrane manufacturer's technical representative, the Owner or Owner's representative, and the Architect or Engineer.
−
−### The conference shall cover the approved submittal assembly, the sequencing of work, vapor retarder installation (if required), deck inspection and acceptance criteria, field quality-control procedures, warranty requirements, and coordination with other trades that penetrate or load the roof membrane.
−
−### The Contractor shall prepare and distribute meeting minutes within five business days.
−
−## Manufacturer's Technical Representative {toc}
−
−### For projects that carry an NDL warranty, the membrane manufacturer's technical representative shall visit the project site at minimum intervals tied to the installation milestones below.
−
−### The technical representative shall visit at the start of membrane installation to observe and approve the substrate and initial installation procedures.
−
−### The technical representative shall visit at the mid-point of membrane installation to observe seaming quality, flashing progress, and fastener patterns.
−
−### The technical representative shall visit at substantial completion, prior to issuing the warranty, to perform the manufacturer's final inspection.
−
−### Representative site visit reports shall be included in the closeout submittal.
−
−## Field Mock-Up {toc}
−
−### Where the project is large enough to warrant it (typically 20,000 square feet of new membrane or more, or at the Owner's direction), the Contractor shall install a field mock-up panel before beginning production installation.
−
−### The Contractor shall install a field mock-up panel of at least 100 square feet before beginning production installation.
−
−### The mock-up shall include at least one field seam, one T-joint, one flashing termination at a vertical wall, and one penetration pipe boot.
−
−### The mock-up shall be reviewed and accepted by the Architect, Owner's representative, and manufacturer's technical representative before production work proceeds.
−
−### The mock-up may remain as part of the finished work if it passes inspection.
−
−## Listing and Labeling {toc}
−
−### All roofing materials and accessories shall be labeled or identified with the applicable listed assembly information.
−
−### Membrane rolls shall bear the manufacturer's product name, thickness, ASTM designation, and applicable FM approval or UL classification.
−
−### Insulation boards shall be labeled with ASTM designation, R-value, and manufacturer's lot number.
−
−### Edge metal that is required to meet ANSI/SPRI ES-1 shall be labeled, tagged, or delivered with documentation confirming the ES-1 test classification.
−
−# Environmental and Substrate Conditions {toc}
−
−## Temperature Restrictions {toc}
−
−### Cold-weather installation increases the risk of membrane stiffness, incomplete adhesive bond, and inadequate seam welds. {note}
−
−### Membrane installation shall not proceed when the ambient air temperature or the substrate temperature is below 40°F (4°C) for thermoplastic (TPO, PVC) systems or below 40°F for EPDM adhesive applications, unless the membrane manufacturer has specifically approved cold-weather procedures and those procedures are submitted and accepted.
−
−```datasheet
−label: Minimum Installation Temperature
−type: radio
−unit: °F
−options:
− - "40°F ambient and substrate (standard practice)"
− - "Below 40°F with manufacturer-approved cold-weather procedures"
−default: "40°F ambient and substrate (standard practice)"
−```
−
−### Where cold-weather installation is unavoidable, the Contractor shall use membrane adhesives and accessories formulated for cold-temperature application, pre-condition membrane rolls in a heated space to at least 50°F before deployment, and protect the work area from wind and precipitation.
−
−### Installation shall not proceed during rain, snow, or fog, or when the deck surface is wet or frost-covered.
−
−### Membrane adhesive application shall not proceed when relative humidity exceeds the adhesive manufacturer's published limit.
−
−### All dew and condensate shall be removed from the deck before installation.
−
−### Pond water remaining on an existing roof surface shall be removed completely before any re-cover or replacement work proceeds.
−
−## Deck Acceptance {toc}
−
−### The Contractor shall inspect the roof deck before installing any membrane assembly components and shall not proceed until the deck meets the conditions below.
−### Proceeding over a deficient deck is not a latent condition for warranty purposes; the Contractor assumes responsibility for any deficiency that is not reported before installation. {note}
−
−### The roof deck type shall be specified for each roof area receiving the membrane assembly.
−
−```datasheet
−label: Roof Deck Type
−type: select
−options:
− - "Structural steel deck — 22 gauge or heavier"
− - "Structural steel deck — lighter than 22 gauge (verify fastener pull-out)"
− - "Cast-in-place or precast concrete"
− - "Lightweight insulating concrete over steel deck"
− - "Wood structural panel (plywood or OSB)"
− - "Gypsum structural concrete"
−drawing_ref: true
−default: "Structural steel deck — 22 gauge or heavier"
−```
−
−### Steel deck shall be free of rust, oil, paint, and surface contamination that would impair adhesion or fastener pull-out strength, and all deck-to-structural framing attachments shall be tight.
−
−### Any loose, deflected, or damaged steel deck panels shall be reported and corrected by others.
−
−### Concrete decks shall be structurally sound, clean, and have a surface profile suitable for adhesive bonding or mechanical fastening, and cracks wider than 1/16 inch shall be documented and reported.
−
−### Wood or lightweight concrete decks shall be assessed for fastener pull-out value per FM Global Data Sheet 1-29 if the fastener pull-out value assumed in the wind-uplift design has not been verified by prior testing for the specific deck type and condition.
−
−### The Contractor shall document in writing any deck deficiency observed and shall not proceed on affected areas until the deck has been corrected and re-inspected.
−
−## Slope and Drainage {toc}
−
−### The roof drainage system design — number, size, and location of primary and overflow drains — is the responsibility of the Designer of Record and shall be coordinated with the structural engineer (overflow drainage design load), the plumbing engineer (drain sizing), and the civil or landscape engineer (discharge routing).
−
−```datasheet
−label: Positive Drainage Method
−type: radio
−options:
− - "Slope inherent in structural framing — no tapered insulation required"
− - "Tapered insulation system — design by insulation manufacturer"
− - "Combination: structural slope supplemented with tapered insulation"
−default: "Tapered insulation system — design by insulation manufacturer"
−```
−
−### The roof deck as-designed shall have a minimum slope of 1/4:12 (1/4 inch per foot) at all points to achieve positive drainage to drains, scuppers, or gutters.
−
−### On structural decks where the framing geometry does not provide this minimum slope throughout, the Contractor shall provide tapered insulation panels designed by the insulation manufacturer to achieve the required slope.
−
−### The tapered insulation design shall be coordinated with the structural engineer when additional dead load affects the structure.
−
−### Crickets shall be provided behind curbs, equipment supports, and other roof obstructions that would otherwise create areas of ponded water.
−
−### This standard governs the membrane assembly at and around drain components; drain sizing and placement shall be [[drawing: as shown on the plumbing and roof-plan drawings]].
−
−# Wind Uplift and Fire Design Basis {toc}
−
−## Wind Uplift Design {toc}
−
−### The zone pressures established by the Designer of Record are the governing design values; the FM-classified assembly and edge metal shall meet or exceed them.
−### FM-classified assemblies are identified by a pressure rating in pounds per square foot (e.g., 1-90 = 90 psf uplift resistance). {note}
−### Perimeter and corner zones require closer fastener spacing or additional rows of fasteners than the field zone. {note}
−
−### Wind-uplift design for the roofing assembly shall comply with ASCE 7, Chapter 26 and Chapter 27 (or Chapter 30 for components and cladding), as adopted by the applicable building code.
−
−```datasheet
−label: Wind Uplift Design Basis
−type: radio
−options:
− - "FM Global — FM-approved assembly required (RoofNav listing)"
− - "ASCE 7 / IBC — engineered attachment per manufacturer testing"
−default: "FM Global — FM-approved assembly required (RoofNav listing)"
−```
−
−### The Designer of Record shall establish the design wind pressures for field, perimeter, and corner zones of the roof based on the building's risk category, mean roof height, exposure category, and basic wind speed from the applicable wind speed map.
−
−### Where the Owner's property insurance is underwritten by FM Global, the roofing assembly shall carry an FM approval rating equal to or exceeding the FM wind-uplift design value calculated per FM Global Data Sheet 1-28.
−
−```datasheet
−label: FM Wind Uplift Classification Required
−type: select
−options:
− - "FM 1-60 (60 psf)"
− - "FM 1-90 (90 psf)"
− - "FM 1-120 (120 psf)"
− - "FM 1-150 (150 psf)"
− - "FM 1-180 (180 psf)"
− - "Per engineering calculation — not FM classified"
−drawing_ref: true
−default: "FM 1-90 (90 psf)"
−```
−
−### The FM RoofNav database shall be the source of assembly listings, and all components (deck, insulation, cover board, membrane, fasteners, and attachment pattern) shall match the listed assembly.
−
−### Substituting components not in the listed assembly voids the FM classification. {note}
−
−### Where FM Global insurance does not govern, the Contractor shall select assemblies that have been tested per FM 4474 or per the membrane manufacturer's published engineering data, and shall verify that the calculated field, perimeter, and corner pressures are within the tested capacity at the specified fastener and plate spacing and pattern.
−
−### The zone boundaries and attachment patterns shall be [[drawing: as indicated on the roof plan wind-zone drawing]].
−
−### The Contractor shall not reduce the specified fastener density in any zone without written approval from the Designer of Record and confirmation that the reduced pattern maintains the required FM or engineered uplift capacity.
−
−## Perimeter Edge Metal Wind Design {toc}
−
−### ES-1 classifies edge metal by the wind pressure it can resist (RE-1, RE-2, and RE-3 test methods for displacement, blow-off, and securement, respectively). {note}
−
−### Perimeter edge metal — including coping caps, gravel stops, fascia, and drip edge — shall be designed and tested in accordance with ANSI/SPRI/FM 4435/ES-1 for resistance to the design wind pressure in the building's perimeter and corner edge zones.
−
−### The specified edge metal assembly shall carry an ES-1 classification rating that meets or exceeds the design edge-zone wind pressure.
−
−```datasheet
−label: Edge Metal ES-1 Minimum Classification Wind Pressure
−type: range
−unit: psf
−drawing_ref: true
−options:
− min: 30
− max: 200
− setpoints: [30, 45, 60, 75, 90, 105, 120, 150, 200]
−default: 75
−```
−
−### IBC Section 1504.5 mandates ES-1 compliance for metal edge securement on low-slope roofs, and this requirement cannot be waived.
−
−### The edge-zone design wind pressure shall be calculated from the ASCE 7 components-and-cladding provisions for the roof perimeter.
−
−### The Designer of Record shall state the design edge pressure on the drawings; the Contractor shall confirm that the specified ES-1-rated edge metal meets that pressure before procurement.
−
−## Fire Classification {toc}
−
−### The classification is an assembly classification, not a membrane-only property; insulation type, cover board, and deck type all influence the fire performance, and substituting any component requires re-confirmation that the new assembly retains the required classification. {note}
−### IBC Table 1505.1 establishes minimum classification (Class A, B, or C) based on construction type. {note}
−
−### The roofing assembly shall achieve the fire classification required by IBC Section 1505 for the building's occupancy and construction type.
−
−```datasheet
−label: Required Fire Classification
−type: radio
−options:
− - "Class A — effective against severe fire exposure (most commercial buildings)"
− - "Class B — effective against moderate fire exposure"
− - "Class C — effective against light fire exposure"
−default: "Class A — effective against severe fire exposure (most commercial buildings)"
−```
−
−### Classification shall be demonstrated by a current UL or listing-agency classification under ASTM E108 / UL 790 for the complete assembly on the specified deck type.
−
−### All project-specific deck and assembly combinations shall be confirmed against the membrane manufacturer's published classified assemblies.
−
−### Single-ply membranes installed over combustible decks require particular attention because the deck's contribution to burning-brand penetration is significant. {note}
−
−# Membrane Materials {toc}
−
−## TPO Membrane — ASTM D6878 {toc}
−
−### TPO is a reinforced, heat-weldable, single-ply thermoplastic membrane whose field seams and all flashing terminations are made using hot-air welding equipment. {note}
−### TPO membrane chemistry uses a base polyolefin polymer (typically polypropylene or a polypropylene/ethylene copolymer) with additives for UV stabilization, flexibility, and fire retardancy, and the membrane is reinforced with a woven polyester or fiberglass scrim. {note}
−### Heat-welded seams, when properly formed, create a bond equal to or stronger than the base membrane. {note}
−
−### The nominal TPO membrane thickness shall be specified based on the anticipated traffic and exposure severity of the roof area.
−
−```datasheet
−label: TPO Membrane Thickness (nominal, over scrim)
−type: radio
−unit: mil
−options:
− - "45 mil (minimum conforming to ASTM D6878)"
− - "60 mil (standard commercial specification)"
− - "80 mil (high-durability; high-traffic or severe-exposure applications)"
−default: "60 mil (standard commercial specification)"
−```
−
−### The TPO membrane sheet width shall be specified consistent with the attachment method used for the roof system.
−
−```datasheet
−label: TPO Membrane Sheet Width
−type: radio
−unit: ft
−options:
− - "6 ft (standard for mechanically attached systems)"
− - "10 ft (standard for fully adhered systems)"
− - "12 ft"
−default: "6 ft (standard for mechanically attached systems)"
−```
−
−### Thermoplastic polyolefin (TPO) membrane shall conform to ASTM D6878/D6878M, Standard Specification for Thermoplastic Polyolefin-Based Sheet Roofing.
−
−### No adhesive or tape seaming is permitted for field seams or flashing seams in TPO systems; all seams shall be hot-air welded.
−
−### ASTM D6878 requires a minimum breaking strength (tensile) of 220 lbf per in width and a minimum seam peel strength of 35 lbf per in width under dry conditions, providing the basis for the weld quality acceptance criteria in this standard.
−
−### The 60-mil thickness is the recommended default for most commercial projects; the 45-mil thickness meets the ASTM minimum but provides less puncture resistance and weld-quality margin and is suitable for lightly loaded, low-traffic roofs only, while the 80-mil thickness is appropriate for roofs with frequent maintenance traffic, heavy equipment loads, hail-prone climates, or extended service life without re-membrane. {note}
−
−### Narrower sheets in mechanically attached systems allow fastener-and-plate rows to be placed within seam overlaps at manageable spacing, while wider sheets in adhered systems reduce the number of seams and associated labor and reduce the number of fastener-and-plate rows in the insulation layers. {note}
−
−## PVC Membrane — ASTM D4434 {toc}
−
−### PVC is a reinforced, heat-weldable thermoplastic membrane with a plasticizer system that provides flexibility at low temperatures. {note}
−### PVC membranes classified as Type II (fiber-reinforced), Type III (fabric-reinforced), or Type IV (fabric-reinforced with fabric backing) are all conforming under ASTM D4434. {note}
−### PVC contains plasticizers that can migrate over time into adjacent materials, particularly certain bituminous insulation facers and adhesives. {note}
−
−### Polyvinyl chloride (PVC) membrane shall conform to ASTM D4434/D4434M, Standard Specification for Poly(Vinyl Chloride) Sheet Roofing.
−
−### Like TPO, all PVC field seams and flashing seams shall be hot-air welded.
−
−### The project shall specify the PVC type required by the FM-approved or UL-classified assembly.
−
−```datasheet
−label: PVC Membrane ASTM D4434 Type
−type: radio
−options:
− - "Type II — fiber-reinforced"
− - "Type III — fabric-reinforced"
− - "Type IV — fabric-reinforced with fabric backing"
−default: "Type III — fabric-reinforced"
−```
−
−### ASTM D4434 requires a minimum of 16 mils of PVC compound over the scrim reinforcement on each face of the reinforcement layer.
−
−```datasheet
−label: PVC Membrane Thickness (nominal)
−type: radio
−unit: mil
−options:
− - "50 mil"
− - "60 mil"
− - "80 mil"
−default: "60 mil"
−```
−
−### All insulation, cover board, and adhesive products used with PVC membrane shall be confirmed by the manufacturer to be plasticizer-migration-compatible.
−
−## EPDM Membrane — ASTM D4637 {toc}
−
−### EPDM is a vulcanized synthetic rubber membrane whose field seams are made with self-adhesive lap tape and seam primer, not hot-air welding. {note}
−### ASTM D4637 covers both non-reinforced and reinforced (fabric- or scrim-backed) EPDM sheet. {note}
−### Proper seam technique depends on surface preparation, adhesive primer application, and roll pressure during seam formation; unlike thermoplastic membranes, EPDM cannot be re-fused once vulcanized, and deviation from the published seam procedure is the leading cause of EPDM seam failure. {note}
−### Reinforced EPDM provides higher resistance to membrane tearing and is preferred for mechanically attached applications where the membrane must span between fastener rows without tearing, while non-reinforced EPDM has superior elongation and conforms more readily to complex flashing geometry.
−
−```datasheet
−label: EPDM Membrane Thickness (nominal)
−type: radio
−unit: mil
−options:
− - "45 mil (minimum; light-duty applications only)"
− - "60 mil (standard commercial specification)"
− - "90 mil (high-durability; hail-prone or high-traffic applications)"
−default: "60 mil (standard commercial specification)"
−```
−
−```datasheet
−label: EPDM Membrane Reinforcement
−type: radio
−options:
− - "Non-reinforced — superior elongation, preferred for adhered flashings"
− - "Reinforced (scrim- or fabric-backed) — preferred for mechanically attached systems"
−default: "Non-reinforced — superior elongation, preferred for adhered flashings"
−```
−
−### Ethylene propylene diene monomer (EPDM) membrane shall conform to ASTM D4637/D4637M, Standard Specification for EPDM Sheet Used in Single-Ply Roof Membrane.
−
−### All EPDM seam work shall follow the membrane manufacturer's current published installation instructions precisely.
−
−### The project shall specify whether non-reinforced or reinforced EPDM is required.
−
−## EPDM Reflectance and Cool-Roof Compliance {toc}
−
−### EPDM is inherently black and a highly effective UV absorber, which contributes to elevated roof surface temperatures relative to white or reflective membranes; white or light-gray TPO or PVC membranes generally have significantly higher initial solar reflectance. {note}
−
−### Where energy codes require a minimum solar reflectance index (SRI) or cool-roof performance, the Designer of Record shall confirm whether EPDM satisfies the energy code requirement for the project's climate zone.
−
−```datasheet
−label: Cool Roof / Energy Code Reflectance Compliance Required
−type: radio
−options:
− - "Yes — membrane reflectance must meet ASHRAE 90.1 or local code"
− - "No — reflectance requirement waived or not applicable"
−default: "No — reflectance requirement waived or not applicable"
−```
−
−### Where cool-roof compliance is required, the Contractor shall submit manufacturer-published or CRRC (Cool Roof Rating Council) tested reflectance and emittance values for the specified membrane.
−
−### EPDM systems that cannot meet the SRI requirement shall not be substituted for a TPO or PVC system that can without written approval from the Designer of Record.
−
−# Insulation and Cover Board {toc}
−
−## Polyisocyanurate Insulation {toc}
−
−### Polyiso is the predominant insulation type used beneath single-ply roofing membranes because of its high R-value per inch, its availability in tapered panels for drainage, and its broad listing in FM-approved and UL-classified roofing assemblies. {note}
−### ASTM C1289 classifies polyiso by type, class, and grade based on compressive strength, facer type, and thermal performance. {note}
−### For new roof construction, ASHRAE 90.1 requires continuous insulation values typically in the R-20 to R-30 range depending on climate zone. {note}
−### ASTM C1289 requires polyiso manufacturers to publish and certify long-term thermal resistance (LTTR) values using a 15-year time-weighted average procedure. {note}
−
−### The facer type for polyisocyanurate insulation shall be specified, coordinating its moisture performance with the roof assembly's vapor retarder strategy.
−
−```datasheet
−label: Polyiso Insulation Facer Type
−type: radio
−options:
− - "Fiber-reinforced felt (standard)"
− - "Coated glass fiber (improved moisture resistance)"
− - "Foil-faced (vapor barrier facer — coordinate with vapor retarder strategy)"
−default: "Fiber-reinforced felt (standard)"
−```
−
−### Polyisocyanurate (polyiso) board insulation shall conform to ASTM C1289, Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board.
−
−### The minimum insulation R-value shall comply with ASHRAE 90.1, Table C5.2 (or the corresponding table in the adopted energy code) for the project's climate zone.
−
−```datasheet
−label: Polyiso Insulation Total Minimum R-Value (LTTR)
−type: range
−unit: "R (h·ft²·°F/BTU)"
−drawing_ref: true
−options:
− min: 15
− max: 40
− setpoints: [15, 20, 25, 30, 35, 40]
−default: 25
−```
−
−### Insulation shall be provided in a minimum of two layers with staggered joints in each direction so that no through joints in the insulation align with joints in an adjacent layer.
−
−```datasheet
−label: Polyiso Installation — Number of Layers
−type: radio
−options:
− - "Two layers, staggered joints (minimum required)"
− - "Three or more layers (high-R assemblies)"
−default: "Two layers, staggered joints (minimum required)"
−```
−
−### Single-layer insulation installation is not permitted because through-joint thermal bridging and wind-uplift stress concentrations at single-layer joints are both significantly worse than in a staggered two-layer installation. {note}
−
−### Contractors and designers shall use the long-term thermal resistance (LTTR) of polyisocyanurate insulation, not the aged or initial-test value, for code compliance demonstration.
−
−## Cover Board {toc}
−
−### NRCA and the major membrane manufacturers all recommend cover boards because polyiso's cellular foam surface does not provide adequate resistance to foot traffic, membrane adhesive absorption, and long-term compressive creep under fastener plates. {note}
−### A cover board also separates the membrane adhesive from the polyiso facer, preventing adhesive incompatibility and migration issues. {note}
−
−### The cover board type installed over the polyisocyanurate insulation shall be specified for each membrane assembly.
−
−```datasheet
−label: Cover Board Type
−type: radio
−options:
− - "High-density polyiso cover board — ASTM C1289 Type II, Class 4 (80 psi minimum compressive strength)"
− - "Glass-mat gypsum board — ASTM C1177"
− - "Perlite board — ASTM C728 Type 2"
− - "High-density wood fiber board"
−default: "High-density polyiso cover board — ASTM C1289 Type II, Class 4 (80 psi minimum compressive strength)"
−```
−
−### The cover board thickness shall be specified for each membrane assembly.
−
−```datasheet
−label: Cover Board Thickness
−type: radio
−unit: in
−options:
− - "1/4 in"
− - "3/8 in"
− - "1/2 in"
−default: "1/2 in"
−```
−
−### A cover board shall be installed over the polyisocyanurate insulation in all fully adhered and mechanically attached membrane assemblies.
−
−### High-density polyiso cover board provides the best combination of compressive strength, thermal contribution, light weight, and compatibility with the polyiso insulation layers below it, and is the recommended default; glass-mat gypsum cover board provides a more dimensionally stable surface for adhered membranes and is preferred where the roof will receive frequent maintenance traffic or where the FM-approved assembly requires it; perlite board is an older, lower-compressive-strength material principally used in re-cover applications where it is already specified by the FM-approved assembly. {note}
−
−### Wood fiber cover board provides good adhesion surface for solvent-based and water-based membrane adhesives but is susceptible to moisture damage if the roof system is breached, and shall not be used in high-humidity or coastal environments without manufacturer confirmation of suitability.
−
−### Where PVC membrane is used, all insulation and cover board products shall be confirmed by the manufacturer to be resistant to plasticizer migration from the PVC membrane.
−
−### Polyiso insulation facers that contain bituminous materials shall not be used in direct contact with PVC membrane because plasticizer migration from PVC into bitumen alters the PVC membrane's physical properties over time.
−
−## Tapered Insulation System {toc}
−
−```datasheet
−label: Tapered Insulation Design
−type: radio
−options:
− - "Not required — positive slope in structural framing"
− - "Tapered insulation — manufacturer's design required (submit for review)"
− - "Tapered insulation with crickets at curbs and equipment supports"
−default: "Tapered insulation — manufacturer's design required (submit for review)"
−```
−
−### Where positive slope is achieved through tapered insulation, the tapered system shall be designed by the insulation manufacturer's technical services group based on the drain locations, roof geometry, and required minimum slope shown on the roof plan.
−
−### The tapered design drawings shall be submitted to the Architect for review before insulation is fabricated and delivered.
−
−### The minimum slope in the tapered field areas shall not be less than 1/4:12 at any point.
−
−### Crickets and saddles around curbs and equipment supports shall be incorporated into the tapered insulation design.
−
−### The Contractor shall not substitute insulation thicknesses from the approved tapered design without the manufacturer's re-analysis and the Designer of Record's approval.
−
−# Vapor Retarder {toc}
−
−## Design Requirement {toc}
−
−### A vapor retarder is not universally required; it is required when the insulation analysis shows that the dew point will occur within or below the insulation assembly under design conditions, creating a risk of condensation that would degrade insulation performance, corrode the deck, or damage interior finishes. {note}
−### Specifying a vapor retarder as a precautionary measure in a low-humidity building in a warm climate can be counterproductive if it traps any incidental moisture that enters the assembly from the exterior. {note}
−
−### The need for a vapor retarder beneath the roof insulation shall be established by a condensation analysis performed by the Designer of Record using the ASHRAE Handbook of Fundamentals dew-point or hygrothermal analysis method, based on the building's interior temperature and relative humidity design conditions and the climate zone's exterior conditions.
−
−### The Designer of Record shall make the vapor retarder determination explicitly.
−
−```datasheet
−label: Vapor Retarder Required
−type: radio
−options:
− - "No — condensation analysis confirms not required"
− - "Yes — condensation analysis confirms required (specify type below)"
−default: "No — condensation analysis confirms not required"
−```
−
−### High-humidity interior environments — food processing facilities, natatoriums, hospitals with high-humidity procedure spaces, laundries, and similar occupancies — almost always require a vapor retarder, whereas standard office, retail, and warehouse interiors in most US climate zones typically do not require one. {note}
−
−## Vapor Retarder Materials {toc}
−
−### Vapor retarder materials vary in permeance from Class I (0.1 perm or less, effectively vapor-impermeable) to Class II (0.1 to 1.0 perm, vapor retarder) to Class III (1.0 to 10 perm). {note}
−
−### Where a vapor retarder is required, it shall be installed directly over the structural deck, below the insulation.
−
−### The vapor retarder shall be compatible with the deck type, the adhesive or fastening method for the bottom insulation layer, and the overall FM-approved or engineered assembly.
−
−### The required permeance class shall be determined by the condensation analysis.
−
−```datasheet
−label: Vapor Retarder Type
−type: radio
−options:
− - "Self-adhering polymer-modified bituminous sheet — Class I (≤0.1 perm)"
− - "Mechanically fastened glass-mat reinforced vapor retarder — Class I or II"
− - "Kraft-faced or film-faced polyiso facer — Class II (coordinate with insulation specification)"
− - "No vapor retarder"
−default: "No vapor retarder"
−```
−
−### Where a self-adhering sheet vapor retarder is used, all seams and end laps shall be rolled to ensure full adhesion.
−
−### Penetrations through the vapor retarder shall be sealed with compatible flashing membrane or tape per the manufacturer's instructions before insulation is installed.
−
−### The vapor retarder shall be protected from foot traffic and UV exposure and shall not be left exposed during multi-day construction halts.
−
−# Attachment and Fastening {toc}
−
−## Attachment Method Selection {toc}
−
−### The three principal attachment methods — mechanically attached, fully adhered, and ballasted — each have distinct structural, thermal, and wind-performance characteristics. {note}
−
−### The attachment method shall be selected based on the required FM wind-uplift classification, the deck type and fastener pull-out value, the building's wind exposure, and the Owner's long-term performance requirements.
−
−```datasheet
−label: Membrane Attachment Method
−type: radio
−options:
− - "Mechanically attached — fastener-and-plate rows at seams"
− - "Fully adhered — membrane bonded to cover board with adhesive"
− - "Ballasted — loose-laid membrane, ballast at minimum 10 lb/sf"
− - "Hybrid — mechanically attached field, adhered perimeter and flashings"
−default: "Mechanically attached — fastener-and-plate rows at seams"
−```
−
−### The attachment method shall be confirmed as part of an FM-approved or tested assembly; mixing attachment methods within a field zone is not permitted without separate FM-listing confirmation.
−
−## Mechanically Attached Systems {toc}
−
−### In mechanically attached systems, the membrane is secured by rows of fasteners and round or bar-shaped plates installed through the membrane at seam overlaps and into the insulation and deck; the membrane spans between fastener rows without bonding to the substrate. {note}
−### This is the most common attachment method for new commercial construction because it is faster to install than a fully adhered system, requires no adhesive cure time, and allows significant drainage-slope tolerances. {note}
−
−### Fastener type, diameter, and embedment depth shall be selected from the FM-approved assembly and shall be appropriate for the deck type.
−
−### Fasteners in steel deck shall be self-drilling, self-tapping screws of the type and length included in the FM-approved assembly.
−
−### Fasteners in concrete or lightweight concrete shall be of the type confirmed by pull-out testing to achieve the minimum required value.
−
−### Fasteners in wood shall be annular-ring-shank roofing screws.
−
−### The fastener-and-plate spacing in the field zone, perimeter zone, and corner zone shall be as specified on the wind-zone attachment drawing.
−
−```datasheet
−label: Field Zone Fastener Spacing (mechanically attached)
−type: select
−unit: in on center
−drawing_ref: true
−options:
− - "6 in o.c. (heavy wind exposure)"
− - "9 in o.c."
− - "12 in o.c. (standard commercial)"
− - "18 in o.c."
−default: deferred
−```
−
−### The Contractor shall not omit fasteners, reduce spacing, or substitute a fastener of different type or length without a revised FM-approval or engineering confirmation.
−
−### Under no circumstances shall the spacing in the perimeter or corner zone be the same as the field-zone spacing.
−
−### Fastener plates shall be round (standard diameter per the FM-approved assembly, commonly 3 inches) or bar-type for wide seam applications.
−
−### Plates shall be of corrosion-resistant steel, properly seated flat on the membrane surface without tilting or tearing.
−
−### Plates installed tilted more than 5 degrees from horizontal shall be removed and replaced.
−
−### The membrane seam lap shall cover all fastener plates by a minimum of 1 inch plus the seam overlap width required for welding, and exposed plate edges after seaming shall be corrected.
−
−## Fully Adhered Systems {toc}
−
−### In fully adhered systems, the membrane is bonded to the cover board or substrate across its entire surface with solvent-based bonding adhesive, water-based bonding adhesive, or two-part spray adhesive. {note}
−### Full adhesion eliminates the "billowing" behavior of mechanically attached membranes under wind uplift, distributes uplift loads across the entire membrane area, and provides better resistance to wind-driven water infiltration at the membrane surface; fully adhered systems are required in many high-wind FM-approved assemblies and are preferred for buildings with reflective metal or glass facades where wind-induced membrane flapping would cause aesthetic or acoustic concerns. {note}
−### Rolling the membrane into wet adhesive traps solvents, while rolling it into fully dry adhesive produces a poor-quality bond. {note}
−
−### The bonding adhesive type shall be specified for each fully adhered membrane installation.
−
−```datasheet
−label: Fully Adhered — Adhesive Type
−type: radio
−options:
− - "Solvent-based bonding adhesive (low temperature performance; VOC restrictions may apply)"
− - "Water-based bonding adhesive (low VOC; temperature-sensitive; longer flash-off)"
− - "Two-part spray adhesive (rapid flash-off; requires spray equipment)"
−default: "Solvent-based bonding adhesive (low temperature performance; VOC restrictions may apply)"
−```
−
−### The Contractor shall follow the adhesive manufacturer's published application rate (typically stated in square feet per gallon for each component or combined).
−
−### The Contractor shall not apply adhesive below the manufacturer's minimum temperature, in high humidity, or onto a wet, frosted, or contaminated substrate.
−
−### Both the membrane and the substrate shall receive adhesive (two-sided application) unless the specific adhesive is formulated for single-sided application.
−
−### Adhesive shall be allowed to flash off (become "tacky dry" — not wet, not fully dry) before the membrane is rolled in.
−
−### The Contractor shall use a hand probe or touch test to confirm flash-off condition immediately before rolling.
−
−### A membrane section rolled into adhesive at incorrect flash-off shall be documented, and if the bond is suspect it shall be probed with a seam probe tool and any unbonded areas remediated.
−
−## Ballasted Systems {toc}
−
−### In ballasted systems, the insulation and membrane are loose-laid over the deck and held in place entirely by the weight of smooth river-washed stone (typically 3/4-inch to 1-1/2-inch gradation) or concrete pavers. {note}
−### Ballasted systems are among the oldest single-ply attachment methods and are simple to install, but they impose significant dead load on the structure (typically 10 to 15 psf for stone ballast). {note}
−
−### Ballasted systems shall not be used where the roof slope exceeds 1:12 (approximately 1 inch per foot) because ballast will migrate under gravity on steeper slopes.
−
−### Ballasted systems shall not be used in high-wind-exposure zones without FM approval confirmation.
−
−### Because the FM-approved assembly accounts for ballast density and gradation, the ballast material used in the field shall match the specification in the FM-approved assembly.
−
−```datasheet
−label: Ballast Type and Weight (ballasted systems only)
−type: radio
−options:
− - "Smooth river-washed stone, 3/4–1-1/2 in gradation, minimum 10 psf"
− - "Smooth river-washed stone, 3/4–1-1/2 in gradation, minimum 12 psf (high wind)"
− - "Concrete pavers, minimum 18 psf"
− - "Not applicable — mechanically attached or adhered system"
−default: "Not applicable — mechanically attached or adhered system"
−```
−
−### Substituting crushed stone, slag, or pea gravel for smooth river-washed stone without FM-approval confirmation is not permitted.
−
−### The structural engineer shall confirm the ballasted system dead load is within the allowable capacity of the deck and framing system before installation.
−
−### The roofing Contractor shall notify the Structural Engineer of Record in writing if the specified ballast loading differs from the structural design loading.
−
−## Insulation Fastening {toc}
−
−### In steel decks, the minimum embedment is typically the full depth of the deck flute plus a minimum of 3/4 inch into the flange (i.e., the fastener reaches through the deck). {note}
−### Under-application of ribbon adhesive is a common field deficiency that reduces the uplift capacity of the assembly. {note}
−
−### Regardless of the membrane attachment method, the insulation layers shall be mechanically fastened to the deck or adhered with insulation adhesive in a pattern that provides the required FM wind-uplift resistance.
−
−```datasheet
−label: Insulation Attachment Method
−type: radio
−options:
− - "Mechanical fasteners and plates (insulation screws and discs)"
− - "Low-rise urethane or polyurethane foam adhesive ribbons"
− - "Full-coverage insulation adhesive"
− - "Per FM-approved assembly — combination of fasteners and adhesive"
−default: "Mechanical fasteners and plates (insulation screws and discs)"
−```
−
−### Insulation boards shall not be loose-laid under a membrane that is subsequently mechanically attached or adhered to the cover board.
−
−### Insulation adhesive shall be applied in ribbons or full coverage as required by the FM-approved assembly.
−
−### Ribbon adhesive patterns shall be the correct bead width, spacing, and number of beads per board as listed.
−
−### The Contractor shall submit the specific adhesive pattern proposed for review as part of the submittal package.
−
−### Mechanical fasteners through insulation into the deck shall penetrate the structural deck by the minimum embedment required for the FM-approved pull-out value.
−
−### Fastener length shall account for all insulation thickness, cover board thickness, and deck geometry, and the Contractor shall calculate and verify fastener length before installation begins.
−
−# Flashings and Terminations {toc}
−
−## General Flashing Requirements {toc}
−
−### Flashings are the highest-risk elements in any membrane roofing assembly. {note}
−### The overwhelming majority of membrane roof failures that produce interior leaks originate at flashings, not at field seams: the field seam is a factory-controlled or welder-controlled straight-line joint, whereas the flashing is a three-dimensional, field-fabricated transition between the plane of the roof membrane and a vertical surface, a penetration, a curb, or a drain. {note}
−### Every change in plane requires flashing, and every flashing requires careful design and execution. {note}
−
−### All membrane flashings shall be the same material as the field membrane or a manufacturer-approved compatible flashing membrane.
−
−### In TPO systems, flashings shall be TPO membrane or prefabricated TPO flashing components and shall be heat-welded to the field membrane, with no adhesive or tape terminations permitted at the seam between the field membrane and the flashing.
−
−### In PVC systems, flashings shall be PVC membrane welded to the field membrane.
−
−### In EPDM systems, flashings shall be EPDM membrane bonded with lap tape and primer, and may also use prefabricated EPDM flashing components (pre-molded corners, pipe boots) adhered with EPDM bonding adhesive.
−
−### Flashing membrane shall extend a minimum of 8 inches above the finished roof membrane surface on all vertical surfaces.
−
−```datasheet
−label: Minimum Flashing Height Above Finished Membrane
−type: radio
−unit: in
−drawing_ref: "roof drawings"
−options:
− - "8 in (minimum)"
− - "12 in (preferred; high-snow or high-debris environments)"
−default: "8 in (minimum)"
−```
−
−### Where parapets, curbs, and walls are less than 8 inches tall, the Designer of Record shall evaluate an alternative detail (through-wall flashing, continuous cant with extended membrane height, or relocation of the base flashing height).
−
−### Eight inches is a widely accepted industry minimum that provides a safety margin against water infiltration from debris damming or localized ponding at the base of vertical surfaces. {note}
−
−### All vertical flashing surfaces shall have a cant strip or a tapered edge strip at the transition from horizontal to vertical to avoid an abrupt 90-degree bend in the membrane.
−
−```datasheet
−label: Cant Strip at Horizontal-to-Vertical Transitions
−type: radio
−options:
− - "45-degree cant, minimum 3 in per face (standard)"
− - "Tapered edge strip — per FM-approved assembly"
− - "No cant (not recommended; requires documentation of alternative)"
−default: "45-degree cant, minimum 3 in per face (standard)"
−```
−
−### A 45-degree cant, minimum 3 inches per face, is standard practice and reduces membrane stress at the corner and provides a gentler transition that is less prone to membrane bridging and cracking. {note}
−
−## Wall and Parapet Flashings {toc}
−
−### Installing a termination bar on a horizontal surface creates a hydrostatic condition where water pools against the bar and is directed under the membrane; this is among the most common termination-bar installation errors. {note}
−
−### At concrete masonry unit, concrete, and structural steel walls, the membrane flashing shall be bonded to the vertical surface with membrane-compatible adhesive and terminated at the top with a metal termination bar.
−
−### Termination bars shall be continuous aluminum or stainless steel angle, minimum 1/8-inch thick, fastened through the membrane into the wall at maximum 12-inch on-center spacing and at maximum 6 inches from each end.
−
−```datasheet
−label: Termination Bar Material
−type: radio
−options:
− - "Aluminum bar, minimum 1/8 in thick"
− - "Stainless steel bar, minimum 1/8 in thick (corrosive environments)"
−default: "Aluminum bar, minimum 1/8 in thick"
−```
−
−```datasheet
−label: Termination Bar Fastener Spacing
−type: radio
−unit: in on center
−options:
− - "6 in o.c. maximum (high wind or loose membrane)"
− - "12 in o.c. maximum (standard)"
−default: "12 in o.c. maximum (standard)"
−```
−
−### Lap sealant shall be applied over the top edge of the termination bar and into the fastener holes as a secondary barrier.
−
−### Termination bars shall be installed on vertical surfaces only.
−
−### On roofs with parapets, the termination bar shall be on the vertical face of the parapet, and the top of the parapet shall be covered by the coping cap system, which is a separate assembly from the membrane flashing.
−
−### At wood-framed or gypsum-sheathed walls, the membrane flashing shall be adhered to the sheathing and the top of the membrane shall be mechanically fastened with a termination bar before the wall cladding is applied.
−
−### The wall cladding shall lap over the top of the membrane flashing by at least 2 inches to prevent water from running behind the membrane at the top termination.
−
−## Roof Drains {toc}
−
−```datasheet
−label: Roof Drain Sump Configuration
−type: radio
−options:
− - "Formed sump in insulation, minimum 12 in radius, minimum 1 in deep"
− - "Prefabricated drain sump — match to drain body manufacturer"
−default: "Formed sump in insulation, minimum 12 in radius, minimum 1 in deep"
−```
−
−### Membrane-roofing-compatible drain bodies shall be cast iron, cast aluminum, or thermoplastic, with a clamping ring that compresses the membrane between the drain body and the clamping ring to form the primary seal.
−
−### The drain body flange shall extend a minimum of 8 inches from the drain center, providing adequate surface area for the membrane-to-drain bond.
−
−### The membrane shall be bonded to the drain flange with adhesive appropriate for the membrane type.
−
−### The clamping ring shall be tightened evenly to the manufacturer's specified torque to create uniform compression without cutting the membrane.
−
−### Drain sumps shall be provided at all interior roof drains to create a recessed collecting area that allows drainage at lower effective water depth than a flat-mounted drain.
−
−### Drain sumps shall be formed in the insulation around each drain, with the sump extending at least 12 inches from the drain center and providing a minimum 1-inch depth below the adjacent finished insulation surface.
−
−### Overflow drains or overflow scuppers are required by IBC Section 1503.4 for all roofs where the primary drainage system could be blocked.
−
−### The overflow system shall be designed by the Designer of Record to handle the 100-year storm event.
−
−### Overflow drain openings shall be located 2 inches above the high point of the primary drainage system so that overflow drains activate only when primary drains are blocked.
−
−### Overflow scuppers shall penetrate the parapet wall and shall be detailed with membrane flashings that prevent water from entering the roof assembly through the scupper opening.
−
−## Penetration Flashings {toc}
−
−### Prefabricated boots are preferred because they are formed consistently, whereas field-fabricated flashings are prone to wrinkles, bridging, and inconsistent seam quality. {note}
−
−### Every penetration through the roof membrane — pipe, conduit, duct, equipment support, structural post — shall be flashed with a manufacturer-supplied or fabricated flashing that isolates the membrane from the penetration and provides a watertight seal.
−
−### The flashing shall accommodate the thermal movement, vibration, and differential settlement between the penetration and the membrane without tearing or debonding.
−
−### Pipe penetrations shall be flashed with prefabricated pipe boots or field-fabricated conical flashings.
−
−```datasheet
−label: Pipe Penetration Flashing Method
−type: radio
−options:
− - "Prefabricated pipe boot — membrane-compatible (preferred)"
− - "Field-fabricated membrane boot — for non-standard pipe diameters"
− - "Pitch pocket — only for complex or clustered penetrations"
−default: "Prefabricated pipe boot — membrane-compatible (preferred)"
−```
−
−### All prefabricated boots shall be heat-welded (TPO, PVC) or adhered with tape and primer (EPDM) to the field membrane.
−
−### Multiple pipes in close proximity shall be individually flashed; grouping multiple pipes into a single pitch pocket or single oversized flashing is not acceptable.
−
−### The use of pitch pockets shall be minimized because they require periodic maintenance refilling as the sealant ages, shrinks, and weathers.
−
−### Where pitch pockets are used, they shall be fabricated from the same material as the field membrane (TPO, PVC) or from metal compatible with the membrane system, sealed with a semi-rigid two-part polyurethane sealant, and sloped to drain.
−
−### The Contractor shall identify all pitch pockets on the as-installed drawing for the Owner's maintenance reference.
−
−## Equipment Curbs and Supports {toc}
−
−### Point loads that indent or compress the insulation beneath the membrane without adequate distribution reduce thermal performance and can create stress concentrations in the membrane that lead to cracking. {note}
−
−### Equipment curbs — roof curbs for HVAC units, exhaust fans, skylights, and similar equipment — shall be minimum 8 inches in height above the finished membrane surface, rigid, and capable of supporting the equipment without differential settlement.
−
−### Curbs shall be pre-fabricated steel or factory-engineered wood; field-fabricated wood curbs shall not be used on NDL warranty projects.
−
−### The membrane shall be wrapped up and over the curb top and clamped under the equipment base frame, with a hook strip or clamping bar at the top of the curb to secure the membrane without puncturing it.
−
−### Blocking and equipment supports that bear directly on the membrane shall use membrane-compatible walkway or pressure-distribution pads.
−
−### Point loads from support legs that are not distributed by pads sufficient to keep contact pressure below the membrane manufacturer's published limit shall not be used.
−
−# Edge Metal {toc}
−
−## Coping Caps {toc}
−
−### Coping caps cover the top of parapet walls and protect both the roofing membrane termination on the inside face of the parapet and the wall construction from water infiltration from above. {note}
−### A typical aluminum coping cap can expand approximately 1/8 inch per 10-foot panel for a 100°F temperature swing. {note}
−
−### The coping cap finish shall be specified for each coping cap installation.
−
−```datasheet
−label: Coping Cap Finish
−type: radio
−options:
− - "Mill finish (aluminum only)"
− - "Factory painted — Kynar 500 or equivalent PVDF coating"
− - "Anodized"
−drawing_ref: true
−default: "Factory painted — Kynar 500 or equivalent PVDF coating"
−```
−
−### Coping cap design, material, gauge, and joint details shall conform to SMACNA Architectural Sheet Metal Manual and shall achieve the ANSI/SPRI ES-1 wind-pressure classification equal to or exceeding the design edge-zone pressure.
−
−```datasheet
−label: Coping Cap Material
−type: radio
−options:
− - "Aluminum, minimum 0.050 in (18 ga) thickness"
− - "Galvanized steel, minimum 24 ga (G90 coating)"
− - "Stainless steel, minimum 24 ga (coastal and corrosive environments)"
− - "Copper, minimum 20 oz per sq ft (historic and premium projects)"
−default: "Aluminum, minimum 0.050 in (18 ga) thickness"
−```
−
−### Coping caps that are not ES-1-tested for the design wind pressure shall not be installed; code compliance (IBC Section 1504.5) and FM Global requirements both mandate ES-1 compliance.
−
−### Coping cap joints shall include a standing seam or slip joint with sufficient thermal expansion allowance for the metal's anticipated temperature range and the cap span between joints.
−
−### Coping cap joints shall be detailed to accommodate thermal movement without stress.
−
−### Coping caps installed without expansion joints or with joints that are sealed rigid with caulk will buckle or crack in temperature extremes. {note}
−
−## Gravel Stops and Fasciae {toc}
−
−### At roof edges without parapets, a gravel stop or fascia edge metal system terminates the roofing assembly, provides a finished edge, and prevents wind from pulling the membrane back from the roof perimeter. {note}
−
−### At roof edges without parapets, a gravel stop or fascia edge metal system shall be installed to terminate the roofing assembly, provide a finished edge, and prevent wind from pulling the membrane back from the roof perimeter.
−
−### The edge metal system shall be ES-1-classified for the design edge wind pressure.
−
−### The membrane shall be sealed under the edge metal cleat or integrated hook strip; exposed membrane edges that are not mechanically clamped and sealed at the perimeter are a primary wind-uplift vulnerability.
−
−## Scuppers {toc}
−
−### Scuppers for overflow drainage or primary drainage through parapet walls shall be formed and flashed with the same membrane or compatible metal flashing material.
−
−### Scupper openings shall be cut cleanly through the parapet; ragged or uneven cuts shall be patched before flashing is applied.
−
−### Scupper flashings shall extend a minimum of 6 inches onto the roof membrane on all sides of the scupper opening and shall be fully bonded.
−
−### Metal scupper liners, where used, shall be set in membrane-compatible sealant and the membrane flashing shall be bonded over the liner flanges.
−
−# Installation {toc}
−
−## Membrane Layout and Seaming {toc}
−
−### Orienting seams parallel to slope prevents cross-slope seams that could collect water; T-joints — the intersection of a field seam with an end lap — represent a three-layer condition that requires special attention in both thermoplastic and EPDM systems. {note}
−
−### Membrane panels shall be laid out before seaming so that seams are oriented parallel to the roof slope direction (perpendicular to the eave or perimeter) wherever practicable.
−
−### End laps (seams perpendicular to the length of the roll) shall be staggered a minimum of 12 inches from adjacent end laps.
−
−## TPO and PVC Seam Welding {toc}
−
−### Properly welded seams fail in the membrane body, not at the weld interface; clean interface separation indicates insufficient weld temperature, speed, or pressure. {note}
−
−### All TPO and PVC field seams and flashing seams shall be made by hot-air welding with automatic or hand-welding equipment.
−
−### The seam overlap shall be a minimum of 1-1/2 inches of welded width for automatic welders and 1 inch for hand welders, measured after welding.
−
−```datasheet
−label: Minimum Field Seam Weld Width (TPO / PVC)
−type: radio
−unit: in
−options:
− - "1-1/2 in welded width (automatic welder)"
− - "1 in welded width (hand welder)"
−default: "1-1/2 in welded width (automatic welder)"
−```
−
−### The weld shall be continuous and shall be probed with a rounded seam probe (cotter pin test) after welding and cooling, and the probe shall not be able to enter the weld without tearing the membrane.
−
−### Any location where the probe penetrates the seam is a void that shall be remediated by cleaning, priming, and re-welding.
−
−### Hot-air welder temperature and speed settings shall be verified at the start of each day and whenever conditions change (ambient temperature, wind, membrane temperature) by welding sample strips and performing peel tests.
−
−### Where peel-test seams separate cleanly at the interface without membrane tearing, the welder settings shall be adjusted before production welding resumes.
−
−### T-joints in TPO and PVC systems shall be treated with a three-corner patch of membrane welded over the intersection to cover the top layer's cut end and any gap that may exist at the three-way corner.
−
−### T-joint patches shall be rounded-corner or circular, minimum 4-inch radius, and shall be fully welded around the perimeter.
−
−### Untreated T-joints are a known leak source and shall not be left without a patch on any completed roof.
−
−## EPDM Seaming {toc}
−
−### EPDM seams do not develop their full strength instantaneously; full bond develops over 24 to 72 hours after seaming under moderate temperature conditions. {note}
−
−### EPDM seams shall be formed using lap tape and primer following the membrane manufacturer's published procedure.
−
−### The seam overlap shall be a minimum of 3 inches.
−
−### The membrane surface in the seam zone shall be cleaned with membrane cleaner or isopropyl alcohol, allowed to fully dry, and then primed with the manufacturer's splice primer.
−
−### Primer shall be allowed to dry to the manufacturer's specified condition before tape is applied.
−
−### Lap tape shall be rolled from one end of the seam to the other without lifting or repositioning to avoid trapping air under the tape.
−
−### The seam shall then be roll-pressed with a hand roller, working from the center of the overlap outward to remove air pockets.
−
−### Seam areas shall be protected from foot traffic, water, and membrane strain for a minimum of 24 hours after seaming.
−
−### EPDM T-joints shall be patched with a minimum 6-inch square patch of membrane applied with lap adhesive and primer, not lap tape, for dimensional stability at the three-way corner.
−
−### Field-cut EPDM edges that are exposed (not covered by a seam lap or patch) shall be treated with edge sealant to prevent peel-back initiation.
−
−## Flashing Installation Sequence {toc}
−
−### The correct sequence prevents the field membrane installation crew from working across incomplete flashings and ensures that partially installed roofs can shed water (even incompletely) during construction rain events. {note}
−
−### Flashings shall be installed in a sequence that ensures all horizontal-to-vertical transitions are complete and watertight before the field membrane installation proceeds in adjacent areas.
−
−### Base flashings at walls shall be in place before the adjacent field membrane is welded to them; installing the field membrane first and then applying flashings on top results in exposed field membrane edges at the base flashing intersection and is not acceptable.
−
−## Walkway Pads {toc}
−
−### Walkway pads protect the membrane from foot traffic and provide slip resistance in wet conditions. {note}
−
−### Membrane walkway pads shall be installed at all roof access hatches, fixed ladders, rooftop mechanical equipment requiring routine maintenance access, and any other locations designated on the roof plan.
−
−### Walkway pads shall be the same membrane material as the field membrane (or a manufacturer-approved compatible material), a minimum of 45 mils thick, and heat-welded (TPO, PVC) or bonded with adhesive (EPDM) to the field membrane.
−
−```datasheet
−label: Walkway Pad Attachment Method
−type: radio
−options:
− - "Heat-welded to field membrane (TPO, PVC systems)"
− - "Bonded with manufacturer-approved adhesive (EPDM systems)"
−default: "Heat-welded to field membrane (TPO, PVC systems)"
−```
−
−### Loose-laid walkway pads are not acceptable because they lift, migrate, and trap water and debris beneath them. {note}
−
−## Protection of Completed Work {toc}
−
−### The Contractor shall protect all completed membrane work from damage by subsequent roofing operations and other trades.
−
−### Membrane surfaces shall not be used as work platforms without plywood protection boards laid over the membrane.
−
−### No direct concentrated loads shall be placed on the membrane from equipment, pallets, or stored material without adequate load distribution.
−
−### Torches, hot equipment, or grinding operations shall not be performed on or adjacent to the installed membrane without a fire watch and protective heat-shielding board.
−
−### The membrane shall be protected from rooftop traffic during the critical initial cure and seam-set period (24 hours for EPDM, immediate for welded TPO and PVC).
−
−### Completed work that is damaged by other trades shall be reported by the Contractor and repaired before the roof is covered or ballasted.
−
−### All repairs shall be documented and included in the as-installed drawing with their locations marked for warranty reference.
−
−# Testing and Inspection {toc}
−
−## Seam Probe Test {toc}
−
−### All seams in thermoplastic (TPO, PVC) membrane systems shall be probed with a rounded-tip seam probe (cotter pin test) after the seam has cooled.
−
−### The probe shall be run continuously along the seam at every accessible seam within the day's production.
−
−### Any seam void — a location where the probe enters the seam without tearing the membrane — shall be circled with chalk and documented.
−
−### Seam voids shall be cut out (using a hot knife or by slitting to clean membrane) and re-welded within the same work day where feasible.
−
−### Seam voids left overnight shall be temporarily sealed with compatible tape before end of day.
−
−### Seam probe testing shall be performed by the seaming operator after each seam cools and by the roofing foreman on a minimum 10 percent spot-check of all seams.
−
−### Discrepancies between the operator's and foreman's tests shall be reviewed with the manufacturer's technical representative.
−
−## Flood Testing {toc}
−
−### ELD using low-voltage or high-voltage methods can detect defects in the membrane that are not visible during visual inspection; ELD is particularly effective over adhered membranes and over membranes installed over conductive cover boards, while its effectiveness over ballasted systems is limited. {note}
−
−### At the Architect's or Owner's direction, or as required by the membrane manufacturer for NDL warranty issuance, flood testing shall be performed by temporarily blocking all drains and flooding the membrane surface with a minimum 2-inch depth of water for a minimum of 24 hours.
−
−### The deck below shall be inspected for leaks during the flood.
−
−### After testing, drains shall be unblocked and the roof shall be allowed to drain completely.
−
−### Flood testing shall not be performed on decks or structures that are not designed for the water load imposed, and the structural engineer shall confirm the allowable load before flood testing is requested.
−
−### Where flood testing is impractical due to structural limits, drain locations, or large roof areas, electronic leak detection (ELD) shall be used as an alternative or supplement.
−
−```datasheet
−label: Post-Installation Leak Testing Method
−type: radio
−options:
− - "Flood test — 2 in depth minimum, 24 hours, confirm structural capacity first"
− - "Electronic leak detection (ELD) — low-voltage vector mapping method"
− - "Visual inspection only — minimum for basic warranty; not recommended for NDL"
− - "Flood test at critical areas + ELD at field"
−default: "Electronic leak detection (ELD) — low-voltage vector mapping method"
−```
−
−## Core Cuts and Substrate Inspection {toc}
−
−### The Architect or Owner's representative may require core cuts — removal of membrane, cover board, and insulation samples at representative locations — to verify that the installed assembly matches the approved submittal and that the substrate is dry and undamaged.
−
−### Core cuts shall be taken at a minimum frequency of one per 10,000 square feet of roof area for NDL warranty projects, or at a frequency directed by the Architect.
−
−### All core cut locations shall be patched immediately after cutting using the same membrane material and a full-width patch welded or bonded over the opening.
−
−### Core cut patch locations shall be marked on the as-installed drawing.
−
−### Core cuts that reveal wet, degraded, or missing insulation layers, mismatched fastener patterns, or any condition that does not match the approved submittal shall be cause for additional investigation, and the Contractor shall not proceed with additional installation until the discrepancy is resolved.
−
−## Final Inspection {toc}
−
−### A final inspection of the completed roofing system shall be performed in the presence of the Contractor, the membrane manufacturer's technical representative, and the Architect or Owner's representative.
−
−### The final inspection shall verify that all seams are probed and documented; all flashings are complete, bonded, and terminated; all penetrations are flashed; all edge metal is installed, sealed, and ES-1-compliant; all walkway pads are bonded; drains are unobstructed and functional; and no membrane is left exposed without termination.
−
−### The manufacturer's technical representative shall issue a written inspection report documenting any deficiencies requiring correction before warranty issuance.
−
−### The Contractor shall correct all deficiencies identified in the final inspection and shall notify the Architect and manufacturer's representative when corrections are complete.
−
−### A follow-up inspection shall be performed to confirm that all deficiencies are resolved before warranty documentation is executed.
−
−# Warranty {toc}
−
−## Contractor's Installation Warranty {toc}
−
−### This warranty is in addition to, and does not substitute for, the membrane manufacturer's warranty. {note}
−
−### The Contractor shall provide a written warranty against defects in workmanship and against leaks attributable to the installation for a minimum of two years from the date of substantial completion.
−
−```datasheet
−label: Contractor Installation Warranty Period
−type: select
−options:
− - "2 years from substantial completion (minimum)"
− - "5 years from substantial completion"
−default: "2 years from substantial completion (minimum)"
−```
−
−### The warranty shall cover the labor and materials required to repair any installation defect.
−
−## Membrane Manufacturer's Warranty {toc}
−
−### Two warranty types are available and shall be specified.
−
−```datasheet
−label: Membrane Manufacturer Warranty Type
−type: radio
−options:
− - "NDL (No Dollar Limit) warranty — full labor and materials, no cap"
− - "Standard (dollar-limit) warranty — prorated materials only"
−default: "NDL (No Dollar Limit) warranty — full labor and materials, no cap"
−```
−### A **standard (dollar-limit) warranty** covers the cost of membrane materials only, subject to a prorated declining cap based on the remaining warranty term, and provides limited protection against major failures late in the warranty term. {note}
−### A **No Dollar Limit (NDL) warranty** covers the full cost of repairing qualifying leaks — labor and materials, without a monetary cap — for the warranty term, and requires an authorized contractor, a manufacturer inspection before issuance, and typically a higher-performance installation (greater thickness, additional flashing detail requirements, or minimum drain sump conditions). {note}
−### The elimination of the dollar cap eliminates the risk of a large mid-warranty repair bill. {note}
−
−### The membrane manufacturer shall provide a written warranty against defects in materials and workmanship, installed by an authorized contractor, for the specified warranty term.
−
−```datasheet
−label: Manufacturer Warranty Term
−type: select
−unit: years
−options:
− - "10 years"
− - "15 years"
− - "20 years"
− - "25 years"
− - "30 years"
−default: "20 years"
−```
−
−### NDL warranties are strongly recommended for new construction and for re-roofing projects where the Owner will carry the building for the full warranty term. {note}
−
−### The Contractor shall confirm NDL warranty eligibility conditions with the specific manufacturer before submittal.
−
−### The Contractor shall identify any project condition that may affect NDL warranty eligibility at the time of submittal, not after installation is complete.
−
−### NDL warranty eligibility typically requires authorized installer status; minimum membrane thickness (often 60 mil minimum for NDL, with 80 mil required for extended terms); specified flashing and penetration details from the manufacturer's published NDL detail set; a manufacturer pre-warranty inspection; and, in some programs, a minimum number of primary and overflow drains above a density threshold. {note}
−
−### Warranty coverage shall include the membrane and all manufacturer-supplied accessories and seam materials; the cover board and insulation layers where included in the manufacturer's assembly warranty; and flashings and penetration boots installed with manufacturer-supplied products.
−
−```datasheet
−label: Warranty Coverage Scope
−type: checkbox
−options:
− - "Membrane and membrane-manufacturer-supplied seam materials"
− - "Cover board (where included in manufacturer assembly warranty)"
− - "Insulation (where included in manufacturer assembly warranty)"
− - "Flashing and penetration components (manufacturer-supplied)"
− - "Edge metal (where included in manufacturer warranty extension program)"
−default: "Membrane and membrane-manufacturer-supplied seam materials"
−```
−
−### Warranty exclusions (typically damage from traffic, abuse, unauthorized modifications, chemical exposure from HVAC discharge, and acts of nature) shall be disclosed to the Owner at the time of contract so that the Owner can establish appropriate maintenance protocols and rooftop access controls.
−
−## Common Warranty Voiding Conditions {toc}
−
−### The Owner shall be informed of the following conditions that typically void or limit the membrane manufacturer's warranty, so that appropriate operational controls can be established.
−
−### Rooftop equipment installation or modifications by other contractors after roof completion, without membrane manufacturer authorization, voids warranty coverage in the area disturbed.
−
−### The mechanical engineer shall locate and route equipment discharge to drains, not to the membrane surface, because HVAC condensate or equipment exhaust discharge directly onto the membrane without proper splash pads and routing produces accelerated degradation.
−
−### Chemical exposure from improper storage, spills, or process emissions shall be avoided, and the specific membrane type's chemical resistance shall be confirmed before the roof is used to store or vent chemicals.
−
−# Common Errors and RFI Generators {toc}
−
−## Low-slope membrane roofing generates a consistent set of field RFIs and installation errors. {note}
−## The following are among the most frequently encountered and are highlighted here so that the Contractor can take proactive steps to avoid them. {note}
−
−## Termination Bar on Horizontal Surfaces {toc}
−
−### Termination bars are designed for vertical application. {note}
−### Installing a termination bar on a horizontal surface — for example, flat on a parapet cap or on a horizontal ledge — creates a water dam that directs water behind the membrane rather than shedding it. {note}
−### All termination bars belong on vertical surfaces with sealant applied to both the top edge of the bar and into the fastener holes. {note}
−
−## T-Joint Voids in Thermoplastic Systems {toc}
−
−### The three-way intersection of two seams in TPO and PVC systems is a geometry challenge because the cut end of the top membrane layer creates a potential void or sharp edge transition. {note}
−### Every T-joint requires a rounded patch, minimum 4-inch radius, fully welded over the intersection. {note}
−### Projects that omit T-joint patching routinely develop leaks at those locations within two to five years. {note}
−
−## Insufficient Flashing Height {toc}
−
−### Base flashings installed at less than 8 inches above the finished membrane surface will be periodically submerged in debris-dammed or ponded water, particularly at parapet bases and around equipment curbs. {note}
−### The 8-inch minimum is a code and industry standard, and all flashings should be measured before concealment.
−
−## Fastener Over-Drive {toc}
−
−### Over-driven fasteners in mechanically attached systems tear through the fastener plate and no longer provide the design pull-out resistance. {note}
−### Fasteners belong driven to the point that the plate is firmly seated without indenting the membrane or pushing the plate into the insulation. {note}
−### Power tools belong set at a torque limit, and hand-driving with a screw gun should be checked against a test pull or torque gauge at the start of each day.
−
−## PVC Membrane Contact with Bituminous Products {toc}
−
−### PVC membrane in contact with bituminous adhesives, bituminous vapor retarders, or coal-tar-based products will suffer plasticizer migration and degradation. {note}
−### All products in the assembly below a PVC membrane must be confirmed by the manufacturer as PVC-compatible.
−
−## Incomplete Adhesive Flash-Off in Fully Adhered Systems {toc}
−
−### Rolling fully adhered membrane into adhesive that is still wet traps solvents and produces an inconsistent, low-strength bond that will allow the membrane to lift under wind uplift. {note}
−### The flash-off condition must be verified before roll-in; adhesive that has dried too far produces equally poor bond.
−### Field mock-ups and daily calibration of flash-off timing are essential on fully adhered projects. {note}
−
−## EPDM Shrinkage at Flashings {toc}
−
−### EPDM has a coefficient of thermal expansion that produces meaningful dimensional change over the temperature range of a roof surface. {note}
−### On poorly adhered or ballasted EPDM systems, the membrane can shrink sufficiently over time to pull base flashings away from vertical surfaces, creating open gaps at the base flashing termination. {note}
−### All EPDM base flashings belong fully adhered to the vertical surface and properly terminated at the top. {note}
−### EPDM shrinkage is also a reason why the minimum flashing overlap onto the field membrane at base flashings is at least 6 inches — a shorter overlap can be pulled completely free by shrinkage. {note}
−
−## Insufficient Scupper Sizing {toc}
−
−### Overflow scuppers that are undersized for the drainage tributary area will not adequately relieve flood loading from the primary drain blocking during a design storm, exposing the structure to loads not included in the structural design. {note}
−### Scupper sizing is the Designer of Record's responsibility but is frequently an RFI item during construction because the indicated size conflicts with the parapet depth or the drain piping. {note}
−### Overflow drainage sizing should be confirmed by the Designer of Record before construction documents are issued.
−
−## Mismatched Insulation and Adhesive in PVC Systems {toc}
−
−### Multiple field cases have documented PVC failure where a non-PVC-compatible polyiso facer was used beneath a fully adhered PVC membrane. {note}
−### The plasticizer from the PVC migrates into the bituminous facer, stiffening the membrane, causing brittleness, and ultimately cracking. {note}
−### Material compatibility confirmation between the membrane, adhesive, and cover board is a required submittal item and must be documented before installation begins.
+---
+title: Membrane Roofing
+category: Building Envelope
+description: >
+ When to use: Roof systems in which a flexible sheet membrane forms the primary weather barrier, together with the insulation, cover board, vapor retarder, attachment, flashings, and terminations that make the membrane work. Covers thermoplastic sheet (TPO, PVC, KEE), thermoset sheet (EPDM), and polymer-modified bitumen sheet (SBS, APP) membranes; mechanically attached, induction-welded, adhered, self-adhered, torch-applied, hot-mopped, cold-adhesive, and ballasted attachment; new construction, tear-off replacement, recover, and partial replacement; wind uplift and fire design basis, field seaming, flashing and termination detailing, field testing, and warranty.
+ Not intended for: Fluid-applied membranes and coating restoration systems ([[sync/fluid-applied-roofing]]); sprayed polyurethane foam roofing; vegetative roof assemblies and their overburden ([[sync/vegetated-roofing]]); discontinuous steep-slope roof coverings such as shingles, tile, slate, and standing-seam panels ([[sync/asphalt-shingle-roofing]], [[sync/metal-roof-panels]]); below-grade and plaza-deck waterproofing ([[sync/below-grade-waterproofing]], [[sync/self-adhering-sheet-waterproofing]]); roof drain, leader, and storm piping sizing and routing ([[sync/roof-drainage]]); architectural sheet metal fabrication and roof specialties beyond their interface with the membrane ([[sync/sheet-metal-flashing-and-trim]], [[sync/roof-specialties-and-copings]]); structural design of the roof deck ([[sync/steel-deck]]).
+---
+
+# Scope {toc}
+
+## Systems Covered {toc}
+
+### This standard covers roof systems in which a flexible sheet membrane, together with its substrate boards, insulation, vapor retarder, attachment, flashings, and terminations, forms the primary weather barrier of the roof. {note}
+
+### Six membrane families are treated as selectable alternatives: thermoplastic polyolefin, polyvinyl chloride, ketone ethylene ester, ethylene propylene diene terpolymer, styrene butadiene styrene polymer-modified bitumen, and atactic polypropylene polymer-modified bitumen. {note}
+
+### These families differ in polymer chemistry, seaming method, surfacing, and service temperature behavior, but they share one design logic: uplift resistance, fire classification, thermal performance, and watertightness are properties of the complete build-up rather than of the membrane sheet alone. {note}
+
+### Governing them in one document keeps detailing, submittal practice, and quality-assurance rigor consistent across the families, so that a project can change membrane family during design without changing the specification's structure. {note}
+
+### The roof assembly shall be composed of components that appear together in the listing, classification, or test report relied on for uplift resistance and fire classification.
+
+### Substitution of any component of a listed or tested assembly shall be resubmitted with evidence that the substituted assembly retains the required uplift resistance and fire classification.
+
+### The Contractor shall not proceed with a substituted assembly until the Engineer of Record has accepted that evidence in writing.
+
+## Work Excluded from This Standard {toc}
+
+### The following work is outside this standard and is governed elsewhere: {note}
+
+- Fluid-applied membranes and roof coating restoration systems — [[sync/fluid-applied-roofing]]
+- Sprayed polyurethane foam roofing
+- Vegetative roof assemblies, growing media, drainage layers, and plantings — [[sync/vegetated-roofing]]
+- Discontinuous steep-slope roof coverings such as shingles, tile, slate, and standing-seam panels — [[sync/asphalt-shingle-roofing]] and [[sync/metal-roof-panels]]
+- Below-grade, plaza-deck, and split-slab waterproofing — [[sync/below-grade-waterproofing]] and [[sync/self-adhering-sheet-waterproofing]]
+- Roof drain body selection, leader sizing, and storm piping design — [[sync/roof-drainage]]
+- Architectural sheet metal fabrication, copings, and roof specialties beyond their interface with the membrane — [[sync/sheet-metal-flashing-and-trim]] and [[sync/roof-specialties-and-copings]]
+- Structural design of the roof deck, its gauge, span, and attachment to the framing — [[sync/steel-deck]]
+- Roof hatches, smoke vents, and skylights as products — [[sync/roof-hatches-and-smoke-vents]]
+- Above-grade wall thermal insulation — [[sync/building-thermal-insulation]]
+- Whole-building air barrier design, of which the roof air barrier is one plane — [[sync/air-barriers]]
+
+## Roofing Work Type {toc}
+
+### Several obligations in this standard exist only because a roof is being placed over existing construction: deck survey, moisture investigation, and the code limits on additional roof coverings. Which of them apply follows from the type of work the project performs. {note}
+
+### The type of roofing work shall be as indicated in the datasheet.
+
+```datasheet
+label: Roofing Work Type
+type: radio
+options:
+ - "New construction over a new roof deck"
+ - "Complete tear-off of the existing roof system down to the deck"
+ - "Recover over the existing roof system"
+ - "Partial replacement of designated roof areas"
+ - "Repair and flashing replacement of an existing roof system"
+```
+
+### Where the work is a recover, the Contractor shall verify and report the number of existing roof coverings in place before ordering materials.
+
+### A recover shall comply with the limits on additional roof coverings and on recover over existing construction in IBC Section 1511.
+
+### Where the existing roof system contains water-saturated insulation or a water-saturated substrate, the saturated material shall be removed rather than recovered.
+
+### Where a partial replacement abuts roof areas that remain in service, the Contractor shall provide a watertight tie-in detail at the boundary of the work and shall submit that detail before the boundary is opened.
+
+# Referenced Standards {toc}
+
+## Materials, design, fabrication, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited in the Contract Documents.
+## Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+
+| Standard | Title |
+|----------|-------|
+| ASCE 7 | Minimum Design Loads and Associated Criteria for Buildings and Other Structures |
+| ASTM C208 | Cellulosic Fiber Insulating Board |
+| ASTM C552 | Cellular Glass Thermal Insulation |
+| ASTM C578 | Rigid, Cellular Polystyrene Thermal Insulation |
+| ASTM C726 | Mineral Wool Roof Insulation Board |
+| ASTM C728 | Perlite Thermal Insulation Board |
+| ASTM C1153 | Location of Wet Insulation in Roofing Systems Using Infrared Imaging |
+| ASTM C1177 | Glass Mat Gypsum Substrate for Use as Sheathing |
+| ASTM C1278 | Fiber-Reinforced Gypsum Panel |
+| ASTM C1289 | Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board |
+| ASTM D1970 | Self-Adhering Polymer Modified Bituminous Sheet Materials Used as Steep Roofing Underlayment for Ice Dam Protection |
+| ASTM D4434 | Poly(Vinyl Chloride) Sheet Roofing |
+| ASTM D4637 | EPDM Sheet Used in Single-Ply Roof Membrane |
+| ASTM D5957 | Flood Testing Horizontal Waterproofing Installations |
+| ASTM D6162 | Styrene Butadiene Styrene (SBS) Modified Bituminous Sheet Materials Using a Combination of Polyester and Glass Fiber Reinforcements |
+| ASTM D6163 | Styrene Butadiene Styrene (SBS) Modified Bituminous Sheet Materials Using Glass Fiber Reinforcements |
+| ASTM D6164 | Styrene Butadiene Styrene (SBS) Modified Bituminous Sheet Materials Using Polyester Reinforcements |
+| ASTM D6222 | Atactic Polypropylene (APP) Modified Bituminous Sheet Materials Using Polyester Reinforcements |
+| ASTM D6223 | Atactic Polypropylene (APP) Modified Bituminous Sheet Materials Using a Combination of Polyester and Glass Fiber Reinforcements |
+| ASTM D6509 | Atactic Polypropylene (APP) Modified Bituminous Base Sheet Materials Using Glass Fiber Reinforcements |
+| ASTM D6754 | Ketone Ethylene Ester Based Sheet Roofing |
+| ASTM D6878 | Thermoplastic Polyolefin Based Sheet Roofing |
+| ASTM D7877 | Electronic Methods for Detecting and Locating Leaks in Waterproofing Membranes |
+| ASTM E108 | Fire Tests of Roof Coverings |
+| ASTM E907 | Field Testing Uplift Resistance of Adhered Membrane Roofing Systems |
+| ANSI/SPRI ES-1 | Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems |
+| ANSI/SPRI FX-1 | Field Test Procedure for Determining the Withdrawal Resistance of Roofing Fasteners |
+| ANSI/SPRI GT-1 | Test Standard for Gutter Systems |
+| ANSI/SPRI RP-4 | Wind Design Standard for Ballasted Single-Ply Roofing Systems |
+| ANSI/SPRI WD-1 | Wind Design Standard Practice for Roofing Assemblies |
+| ASHRAE 90.1 | Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings |
+| CRRC-1 | Radiative Property Product Rating Program Standard |
+| FM 4470 | Single-Ply, Polymer-Modified Bitumen Sheet, Built-Up Roof, and Liquid Applied Roof Assemblies for Use in Class 1 and Noncombustible Roof Deck Construction |
+| FM 4474 | Evaluating the Simulated Wind Uplift Resistance of Roof Assemblies Using Static Positive and/or Negative Differential Pressures |
+| FM Global Data Sheet 1-28 | Wind Design |
+| FM Global Data Sheet 1-29 | Roof Deck Securement and Above-Deck Roof Components |
+| IBC | International Building Code, Chapter 15 — Roof Assemblies and Rooftop Structures |
+| IECC | International Energy Conservation Code |
+| UL 580 | Tests for Uplift Resistance of Roof Assemblies |
+| UL 790 | Standard Test Methods for Fire Tests of Roof Coverings |
+| UL 1256 | Fire Test of Roof Deck Constructions |
+| UL 1897 | Uplift Tests for Roof Covering Systems |
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The membrane, insulation, cover board, attachment, and edge-metal submittals describe one tested assembly. Reviewing them separately allows a component swap to pass review that the listing would not permit, which is why this standard requires them as a single package. {note}
+
+### The Contractor shall submit the following for review and acceptance as one package before materials are procured or installation begins:
+
+- Membrane product data confirming the governing ASTM specification, nominal and minimum thickness, reinforcement type, and surfacing
+- Insulation, cover board, and vapor retarder product data with the governing material specification for each
+- Adhesive, primer, seam tape, lap sealant, and accessory product data, including published application rates and temperature limits
+- Fastener and stress plate product data, including corrosion-resistance evidence and required embedment for the deck type
+- Assembly listing, classification, or test report establishing uplift resistance for the complete as-specified build-up on the specified deck
+- Fire classification listing for the complete assembly on the specified deck type and slope
+- ANSI/SPRI ES-1 test evidence for every perimeter edge system, coping, and fascia that terminates the membrane
+- Shop drawings showing membrane layout, seam and lap orientation, attachment pattern by roof zone, and each flashing and termination condition
+- Tapered insulation layout drawings where a tapered system is specified, showing board thicknesses, crickets, saddles, and drain sumps
+- Installer qualification evidence
+- The proposed warranty forms and the conditions the manufacturer places on issuing them
+
+```datasheet
+label: Action Submittals Required
+type: checkbox
+options:
+ - "Membrane product data with governing ASTM specification and thickness"
+ - "Insulation, cover board, and vapor retarder product data"
+ - "Adhesive, primer, seam tape, lap sealant, and accessory product data"
+ - "Fastener and stress plate product data with corrosion evidence"
+ - "Assembly uplift listing, classification, or test report"
+ - "Fire classification listing for the complete assembly"
+ - "ANSI/SPRI ES-1 test evidence for perimeter edge systems"
+ - "Shop drawings for layout, attachment zones, flashings, and terminations"
+ - "Tapered insulation layout drawings"
+ - "Installer qualification evidence"
+ - "Proposed warranty forms and issuance conditions"
+default:
+ - "Membrane product data with governing ASTM specification and thickness"
+ - "Insulation, cover board, and vapor retarder product data"
+ - "Adhesive, primer, seam tape, lap sealant, and accessory product data"
+ - "Assembly uplift listing, classification, or test report"
+ - "Fire classification listing for the complete assembly"
+ - "ANSI/SPRI ES-1 test evidence for perimeter edge systems"
+ - "Shop drawings for layout, attachment zones, flashings, and terminations"
+ - "Installer qualification evidence"
+ - "Proposed warranty forms and issuance conditions"
+```
+
+### Product data submitted as a marked catalog page shall have the proposed product, thickness, and options clearly identified.
+
+## Informational Submittals {toc}
+
+### The Contractor shall submit the following for information before the pre-installation conference:
+
+- Safety data sheets for adhesives, primers, cleaners, sealants, and coatings to be used on the project
+- A written cold-weather or hot-weather installation procedure where installation is planned outside the temperature limits established in this standard
+- The proposed fastener withdrawal test procedure and locations where withdrawal testing is specified
+- The proposed sequence of work, including how partially completed areas will be made watertight at the end of each work period
+- A schedule of the temporary loads the Contractor intends to place on the completed membrane, including equipment, staging, and material storage
+
+```datasheet
+label: Informational Submittals Required
+type: checkbox
+options:
+ - "Safety data sheets for adhesives, primers, cleaners, and coatings"
+ - "Written cold-weather or hot-weather installation procedure"
+ - "Fastener withdrawal test procedure and locations"
+ - "Sequence of work and nightly water cut-off method"
+ - "Schedule of temporary rooftop loads"
+default:
+ - "Safety data sheets for adhesives, primers, cleaners, and coatings"
+ - "Sequence of work and nightly water cut-off method"
+```
+
+## Closeout Submittals {toc}
+
+### The Contractor shall submit the following before final acceptance and before the manufacturer warranty is executed:
+
+- The executed and dated manufacturer warranty for the assembly and term specified
+- The executed Contractor workmanship warranty
+- The manufacturer inspection report and the Contractor's written response resolving each item on it
+- Reports for every field test performed, including seam verification, withdrawal tests, flood tests, electronic leak detection, and core cuts
+- Record drawings showing membrane and lap layout, drain and scupper locations, penetrations, curbs, sealant-filled pitch pockets, and the location of every field repair
+- Material certifications confirming that the membrane, insulation, and cover board delivered to the project conform to the specified material standards
+- Roof maintenance instructions covering inspection frequency, permitted cleaning methods, and the procedure for authorizing rooftop work after acceptance
+
+```datasheet
+label: Closeout Submittals Required
+type: checkbox
+options:
+ - "Executed and dated manufacturer warranty"
+ - "Executed Contractor workmanship warranty"
+ - "Manufacturer inspection report and resolution of each item"
+ - "Field test reports for seams, withdrawal, flood, leak detection, and cores"
+ - "Record drawings of layout, penetrations, and repairs"
+ - "Material certifications for membrane, insulation, and cover board"
+ - "Roof maintenance instructions for the Owner"
+default:
+ - "Executed and dated manufacturer warranty"
+ - "Executed Contractor workmanship warranty"
+ - "Manufacturer inspection report and resolution of each item"
+ - "Field test reports for seams, withdrawal, flood, leak detection, and cores"
+ - "Record drawings of layout, penetrations, and repairs"
+ - "Material certifications for membrane, insulation, and cover board"
+ - "Roof maintenance instructions for the Owner"
+```
+
+### Record drawings shall be delivered in an editable electronic format as well as in the reproducible format the Contract Documents require for closeout.
+
+# Quality Assurance {toc}
+
+## Installer Qualifications {toc}
+
+### Manufacturer authorization programs generally require completed training, a record of completed installations, and periodic renewal. Where a manufacturer conditions its system warranty on authorized installation, the qualification requirement and the warranty requirement are the same decision seen twice. {note}
+
+### The qualification basis for the roofing installer shall be as indicated in the datasheet.
+
+```datasheet
+label: Installer Qualification Basis
+type: checkbox
+options:
+ - "Current membrane manufacturer authorization for the specified system"
+ - "Documented completion of comparable low-slope membrane projects"
+ - "Foreman experience meeting the minimum stated in this standard"
+ - "Qualified welding operators for heat-welded membrane systems"
+ - "Certified torch applicators for torch-applied membrane systems"
+default:
+ - "Current membrane manufacturer authorization for the specified system"
+ - "Foreman experience meeting the minimum stated in this standard"
+```
+
+### The Contractor shall submit evidence of each qualification indicated in the datasheet before the action submittal package is accepted.
+
+### Where manufacturer authorization is indicated, the authorization shall be current at the start of the work and shall be maintained through final acceptance.
+
+### The roofing foreman assigned to the project shall have not less than five years of documented field experience with the membrane family being installed.
+
+### Where the Contractor proposes to replace the qualified foreman during the work, the replacement's qualifications shall be submitted and accepted before the change takes effect.
+
+## Welding and Torch Operator Qualification {toc}
+
+### A hot-air weld is made by a machine setting rather than by a material specification, so the operator and the equipment together are the quality control. Ambient temperature, wind, membrane surface temperature, and line voltage all shift the setting that produces a sound weld. {note}
+
+### Each hot-air welding operator shall produce acceptable test welds on the project membrane before production welding begins.
+
+### Test welds shall be made at the start of each work period and again whenever ambient temperature, wind, or membrane surface temperature changes enough to affect the weld.
+
+### Each test weld shall be peel-tested, and the weld shall be accepted only where separation occurs by tearing of the membrane rather than by clean separation at the weld interface.
+
+### Test weld results, including welder settings, shall be recorded and made available to the Engineer of Record on request.
+
+### Where torch-applied membrane is installed, the torch applicator shall hold a current certification for torch application and the Contractor shall maintain a fire watch as required by the Contract Documents and the Authority Having Jurisdiction.
+
+## Pre-Installation Conference {toc}
+
+### A pre-installation conference shall be held before roofing work begins.
+
+### The conference shall be attended by the Contractor, the roofing foreman, the Owner or the Owner's representative, the Engineer of Record, and each trade whose work penetrates, bears on, or terminates against the roof membrane.
+
+### The conference shall cover the accepted assembly, the sequence of work, deck acceptance criteria, vapor retarder and air barrier continuity, attachment patterns by roof zone, field quality control, temperature and weather limits, warranty conditions, and rooftop load and access control after acceptance.
+
+### The Contractor shall record and distribute conference minutes within five business days of the conference.
+
+## Manufacturer Field Representation {toc}
+
+### Manufacturer field visits are the mechanism by which a system warranty is underwritten; the same visits also catch attachment and flashing deviations while they can still be corrected without demolition. {note}
+
+### Manufacturer field representation shall be as indicated in the datasheet.
+
+```datasheet
+label: Manufacturer Field Representation
+type: checkbox
+options:
+ - "Attendance at the pre-installation conference"
+ - "Site visit at the start of membrane installation"
+ - "Interim site visits during membrane installation"
+ - "Final inspection before warranty issuance"
+ - "Written report for each site visit"
+default:
+ - "Attendance at the pre-installation conference"
+ - "Final inspection before warranty issuance"
+ - "Written report for each site visit"
+```
+
+### Reports from each manufacturer site visit shall be included in the closeout submittal.
+
+### The Contractor shall provide safe access and shall coordinate scheduling so that each specified manufacturer visit occurs at the installation milestone it is intended to observe.
+
+## Field Mock-Up {toc}
+
+### A mock-up converts the detailing argument from drawings into an object the parties can stand on, and it fixes welder settings, adhesive flash-off timing, and flashing sequence before those choices are replicated across the roof. {note}
+
+### Whether a field mock-up is required shall be as indicated in the datasheet.
+
+```datasheet
+label: Field Mock-Up
+type: radio
+options:
+ - "No mock-up required"
+ - "Mock-up panel required before production installation"
+ - "Mock-up panel required and retained as part of the finished work"
+```
+
+### Where a mock-up is required, it shall be not less than 100 square feet of the specified assembly built on the project deck.
+
+### The mock-up shall include at least one field seam, one lap intersection, one base flashing at a vertical surface, and one penetration flashing.
+
+### The mock-up shall be reviewed and accepted by the Engineer of Record and, where manufacturer field representation is specified, by the manufacturer's representative before production installation proceeds.
+
+### The accepted mock-up shall establish the standard of workmanship for the remainder of the work.
+
+### Where the datasheet indicates the mock-up is retained in the finished work, the mock-up shall be integrated into the completed roof and shall carry the same warranty as the surrounding roof.
+
+## Product Identification and Labeling {toc}
+
+### Membrane rolls shall bear the manufacturer name, product designation, nominal thickness, and the governing material specification.
+
+### Insulation and cover boards shall bear the manufacturer name, the governing material specification, and the thermal resistance where the product is a thermal insulation.
+
+### Fastener and stress plate packaging shall identify the product designation and the deck types for which the fastener is listed.
+
+### Perimeter edge systems required to meet ANSI/SPRI ES-1 shall be labeled, tagged, or delivered with documentation identifying the tested classification.
+
+### Materials delivered without the identification required above shall not be incorporated into the work until the Contractor provides equivalent documented traceability to the accepted submittal.
+
+# Environmental and Substrate Conditions {toc}
+
+## Ambient and Surface Temperature Limits {toc}
+
+### Low temperature affects the three bonding mechanisms differently: solvent-based adhesive flashes off more slowly and can be trapped, tape splices develop bond more slowly, and thermoplastic sheet stiffens so that the welder puts more heat into a colder substrate. Each has a different cure, which is why the limit belongs to the product rather than to the calendar. {note}
+
+### High membrane surface temperature is the mirror problem: a dark membrane in full sun can exceed the adhesive's open time before the sheet is rolled in, and a hot thermoplastic sheet welds at a lower machine setting than the same sheet welds at first light. {note}
+
+### The minimum ambient and substrate temperature at which installation may proceed shall be as indicated in the datasheet.
+
+```datasheet
+label: Minimum Ambient and Substrate Installation Temperature
+type: range
+unit: °F
+options:
+ min: -20
+ max: 60
+ step: 5
+```
+
+### Where the datasheet does not establish a minimum installation temperature, the published minimum application temperature of the membrane, adhesive, primer, and sealant being used shall govern, and the Contractor shall report those limits at the pre-installation conference.
+
+### Installation shall not proceed below the governing minimum temperature unless the membrane manufacturer has issued a written cold-weather procedure for the specific products in use and that procedure has been submitted and accepted.
+
+### Where a cold-weather procedure is used, membrane and accessory rolls shall be conditioned in heated storage before deployment and shall be returned to heated storage at the end of each work period.
+
+### Adhesive and primer shall be conditioned to the temperature range published for the product before application and shall not be thinned to compensate for temperature.
+
+### Where membrane surface temperature exceeds the adhesive's published maximum application temperature, adhesive work shall be rescheduled to a cooler part of the work period rather than proceeding at a reduced open time.
+
+## Precipitation and Surface Moisture {toc}
+
+### Membrane installation shall not proceed during rain, snow, sleet, or fog.
+
+### Membrane installation shall not proceed where the substrate carries standing water, frost, ice, dew, or condensate.
+
+### The Contractor shall remove all surface moisture from the substrate and shall confirm the substrate is dry immediately before each area is covered.
+
+### The Contractor shall provide temporary water cut-offs at the end of each work period so that no part of the assembly is left open to precipitation.
+
+### Temporary water cut-offs shall be removed and the cut-off area shall be cut back to sound, dry material before work resumes in that area.
+
+### Any insulation, cover board, or substrate that becomes wet before it is covered by the membrane shall be removed and replaced at the Contractor's cost.
+
+## Roof Deck Acceptance {toc}
+
+### Deck condition is the one variable the roofing Contractor inherits rather than installs, and it governs fastener withdrawal, adhesive bond, and the flatness the membrane will telegraph. Accepting the deck by proceeding transfers responsibility for it. {note}
+
+### The roof deck type shall be as indicated in the datasheet.
+
+```datasheet
+label: Roof Deck Type
+type: select
+options:
+ - "Steel roof deck"
+ - "Cast-in-place structural concrete"
+ - "Precast concrete plank or tee"
+ - "Structural lightweight insulating concrete over steel deck"
+ - "Gypsum structural concrete"
+ - "Cementitious wood fiber deck plank"
+ - "Wood structural panel sheathing"
+ - "Solid wood plank or heavy timber decking"
+ - "Existing roof system serving as the recover substrate"
+drawing_ref: "structural drawings"
+default: deferred
+```
+
+### The Contractor shall inspect the deck for the full area of the work before installing any component of the assembly.
+
+### The Contractor shall report every deck deficiency in writing before covering the affected area.
+
+### Steel deck shall be free of oil, loose rust, ponded water, and coatings that impair fastener seating or adhesive bond, and all deck-to-framing attachments shall be complete and tight.
+
+### Concrete decks shall be cured, sound, and clean, and shall be dry to the moisture criterion published for the adhesive or primer that will be applied to them.
+
+### Cracks, spalls, honeycombing, and surface irregularities in a concrete deck that would prevent continuous support of the assembly shall be reported and repaired by others before roofing proceeds.
+
+### Wood decks shall be securely fastened, free of protruding fasteners, and free of decayed or delaminated material.
+
+### Lightweight insulating concrete and gypsum concrete decks shall be dry, sound, and shall have achieved the compressive strength required by the fastener listing before fasteners are installed.
+
+### Where the datasheet indicates an existing roof system as the recover substrate, the existing surface shall be swept clean, blisters and ridges shall be cut and made flat, and loose aggregate shall be removed or embedded.
+
+### The Contractor shall not proceed over a deficient deck area until the deficiency has been corrected and the area re-inspected.
+
+### Where the parties disagree whether a deck condition is a deficiency, the Engineer of Record shall make the initial determination.
+
+## Existing Roof Survey {toc}
+
+### A moisture survey of an existing roof answers a question that no visual inspection can: whether insulation that looks intact is holding water that will be sealed under the new membrane. {note}
+
+### Where the roofing work type is a recover or a partial replacement, the Contractor shall survey the existing roof for entrapped moisture before the new assembly is installed.
+
+### The moisture survey shall use infrared thermographic imaging per ASTM C1153, a capacitance or nuclear moisture meter, or verification cuts, and the method used shall be recorded in the survey report.
+
+### Areas identified as wet by the survey shall be opened and verified by cut, and wet material shall be removed to sound, dry construction.
+
+### The Contractor shall submit the survey report, marked with the extent of wet material found, before the new assembly is installed over the surveyed area.
+
+### The cost of removing and replacing wet material beyond the quantity carried in the Contract Documents shall be handled as a change in the work.
+
+## Roof Slope and Drainage {toc}
+
+### Slope is what turns a waterproofing layer into a roof. Water that stands on a membrane extends the exposure of seams and terminations, carries the debris that dams flow, and imposes a sustained load the deck was not necessarily designed to hold. {note}
+
+### For new low-slope roof construction, the model codes establish a minimum design slope for membrane roofs; a lesser design slope arises on re-roofing work where the existing structure sets the geometry and the code's existing-building provisions permit the condition to remain. This standard admits the full range so that a re-roof can record what the building actually has, rather than recording a value the roof does not meet. {note}
+
+### The design roof slope to drainage shall be as indicated in the datasheet.
+
+```datasheet
+label: Design Roof Slope to Drainage
+type: range
+unit: in./ft
+drawing_ref: "roof plan"
+options:
+ min: 0
+ max: 6
+ step: 0.125
+default: deferred
+```
+
+### The completed roof shall drain to the primary drainage points without ponding, measured 48 hours after the end of a rain event under conditions permitting drainage.
+
+### Where the structural framing does not provide the design slope, positive slope shall be established with tapered insulation, tapered fill, or crickets as indicated in the datasheet.
+
+### Where the design roof slope is less than the minimum the adopted code requires for new construction, the Engineer of Record shall record on the Contract Documents the code provision under which the lesser slope is permitted.
+
+### Where the design roof slope exceeds 2 inches per foot, the membrane shall be back-nailed or otherwise restrained against slippage in accordance with the membrane manufacturer's published requirements for the slope.
+
+### Where the design roof slope exceeds 2 inches per foot, ballasted attachment shall not be used, in accordance with IBC Section 1504.5 and ANSI/SPRI RP-4.
+
+### Primary and secondary drainage capacity, drain and scupper sizing, and the rain load imposed on the structure shall be established by the Engineer of Record in accordance with IBC Section 1502 and IBC Section 1611.
+
+### Crickets and saddles shall be provided on the upslope side of curbs, equipment supports, expansion joints, and other obstructions wider than 24 inches that would otherwise impound water.
+
+### The membrane assembly shall be terminated at drains, scuppers, and gutters in the manner required by this standard; drain body selection and storm piping design are governed by [[sync/roof-drainage]].
+
+# Wind Uplift Design Basis {toc}
+
+## Design Uplift Pressures {toc}
+
+### Wind uplift on a roof is not uniform. Flow separation at the roof edge and vortex formation at the corners produce suctions several times the field-zone value over a small fraction of the roof area, which is why attachment is specified by zone rather than by a single number. {note}
+
+### Design uplift pressures are a structural output, not a product selection: they follow from the building's risk category, mean roof height, exposure category, enclosure classification, and the basic wind speed for the site. The roofing datasheet records them so that the assembly can be checked against them. {note}
+
+### The design uplift pressures for the field, perimeter, and corner zones of the roof shall be established by the Engineer of Record in accordance with ASCE 7 and the adopted building code, and shall be as indicated in the datasheet.
+
+```datasheet
+label: Design Uplift Pressure — Field Zone
+type: range
+unit: psf
+drawing_ref: "roof plan wind zone diagram"
+options:
+ min: 0
+ max: 500
+ step: 1
+default: deferred
+```
+
+```datasheet
+label: Design Uplift Pressure — Perimeter Zone
+type: range
+unit: psf
+drawing_ref: "roof plan wind zone diagram"
+options:
+ min: 0
+ max: 500
+ step: 1
+default: deferred
+```
+
+```datasheet
+label: Design Uplift Pressure — Corner Zone
+type: range
+unit: psf
+drawing_ref: "roof plan wind zone diagram"
+options:
+ min: 0
+ max: 500
+ step: 1
+default: deferred
+```
+
+### The extent of the perimeter and corner zones shall be [[drawing: as indicated on the roof plan wind zone diagram]].
+
+### Where the Owner's property insurer imposes uplift criteria that exceed the code-derived design pressures, the insurer's criteria shall govern and shall be reflected in the pressures recorded in the datasheet.
+
+## Assembly Uplift Resistance {toc}
+
+### An uplift rating belongs to an assembly, not to a membrane. The deck gauge and span, the fastener and its embedment, the insulation type and thickness, the cover board, the adhesive pattern, and the membrane are all variables in the tested result. {note}
+
+### The basis on which the assembly's uplift resistance is established shall be as indicated in the datasheet.
+
+```datasheet
+label: Assembly Uplift Resistance Basis
+type: radio
+options:
+ - "FM Approvals assembly listing"
+ - "UL 580 assembly classification"
+ - "UL 1897 assembly uplift test report"
+ - "FM 4474 assembly uplift test report"
+ - "ANSI/SPRI WD-1 design calculation"
+ - "ANSI/SPRI RP-4 ballasted system design"
+ - "Membrane manufacturer published engineered attachment tables"
+```
+
+### The listed, classified, or calculated uplift resistance of the assembly shall equal or exceed the design uplift pressure for each roof zone.
+
+### Every component of the installed assembly shall appear in the listing, classification, or test report relied on, including the deck type and gauge, fastener type and length, insulation type and thickness, cover board, and attachment pattern.
+
+### Where the assembly uplift basis is a design calculation rather than a tested assembly, the calculation shall be submitted with the action submittal package and shall be sealed where the Contract Documents or the Authority Having Jurisdiction require a sealed calculation.
+
+### Nonballasted roof assemblies shall satisfy IBC Section 1504.4, and ballasted low-slope single-ply assemblies shall satisfy IBC Section 1504.5.
+
+## Zone Enhancement and Fastener Density {toc}
+
+### Fastener and adhesive density in each roof zone shall be as required by the assembly listing, classification, or test report that establishes the uplift resistance for that zone.
+
+### Attachment density in the perimeter and corner zones shall be increased relative to the field zone by the amount the governing listing, classification, or test report requires.
+
+### The Contractor shall not reduce fastener count, increase fastener spacing, or substitute a fastener or plate of different type, diameter, or length from that in the governing listing.
+
+### Where the Contractor proposes an attachment change, the change shall be accompanied by a revised listing reference or a revised calculation demonstrating that the design uplift pressure is still met in every zone, and shall be accepted by the Engineer of Record before installation.
+
+### The Contractor shall verify the installed attachment pattern in each zone against the shop drawings before the pattern is concealed by the next layer.
+
+## Perimeter Edge Securement {toc}
+
+### The roof edge is where uplift is highest and where the membrane assembly is mechanically weakest, because the load path passes from a continuous membrane into a discontinuous metal component and its fasteners. An edge system that releases exposes the membrane to peel from its most-loaded boundary. {note}
+
+### Perimeter edge systems, including copings, gravel stops, fascia, and drip edge, shall be tested in accordance with Test Methods RE-1, RE-2, and RE-3 of ANSI/SPRI ES-1 as required by IBC Section 1504.6.
+
+### The ES-1 classification of the specified edge system shall equal or exceed the design wind pressure at the roof edge determined in accordance with ANSI/SPRI ES-1.
+
+### Gutters used to secure the perimeter edge of the membrane shall be tested in accordance with Test Methods G-1 and G-2 of ANSI/SPRI GT-1 as required by IBC Section 1504.6.1.
+
+### Edge system fastener type, spacing, and substrate anchorage shall match the tested configuration on which the ES-1 classification is based.
+
+### Perimeter edge systems shall be furnished, fabricated, and finished in accordance with [[sync/roof-specialties-and-copings]] and [[sync/sheet-metal-flashing-and-trim]]; this standard governs their interface with the membrane.
+
+# Fire Performance {toc}
+
+## Roof Covering Fire Classification {toc}
+
+### A roof covering fire classification describes how the assembly behaves under external fire exposure: flame spread across the surface, resistance to burning brands, and whether the fire penetrates to the deck. Because deck type, insulation, cover board, and surfacing all participate, the classification is earned by the assembly as tested. {note}
+
+### The roof covering fire classification required for the building shall be established from IBC Section 1505 and Table 1505.1 for the construction type and occupancy, and shall be as indicated in the datasheet.
+
+```datasheet
+label: Roof Covering Fire Classification
+type: radio
+options:
+ - "Class A — resistance to severe fire test exposure"
+ - "Class B — resistance to moderate fire test exposure"
+ - "Class C — resistance to light fire test exposure"
+ - "No fire classification required by the adopted code for this building"
+default: "Class A — resistance to severe fire test exposure"
+```
+
+### The classification shall be demonstrated by a current listing under ASTM E108 or UL 790 for the complete assembly on the specified deck type and at the specified slope.
+
+### The listing relied on shall cover the slope of the roof area to which it is applied, because a classification established at one slope does not extend to a steeper one.
+
+### Where more than one deck type occurs within the scope of the work, a classified assembly shall be identified for each deck type.
+
+## Roof Deck Construction Fire Requirements {toc}
+
+### Foam plastic insulation over a steel deck introduces a fire load on the underside of the assembly that the roof covering classification does not address, which is why a separate deck construction requirement exists. {note}
+
+### The fire requirement applying to the roof deck construction shall be as indicated in the datasheet.
+
+```datasheet
+label: Roof Deck Construction Fire Requirement
+type: radio
+options:
+ - "No requirement beyond the roof covering fire classification"
+ - "UL 1256 roof deck construction classification"
+ - "FM Approvals Class 1 roof deck assembly"
+ - "Thermal barrier over the deck as required for foam plastic insulation"
+```
+
+### Where the datasheet indicates a deck construction requirement, the assembly submitted shall carry the corresponding classification or shall include the thermal barrier the classification requires.
+
+### Where foam plastic insulation is installed over a steel deck, the assembly shall include the thermal barrier, coverage limits, or joint treatment required by the classification relied on.
+
+# Membrane Selection {toc}
+
+## Membrane Material {toc}
+
+### All six membrane families in this standard are code-recognized and available from multiple manufacturers in the North American market. They differ along axes an engineer can evaluate for a specific building: seaming mechanism, chemical resistance, behavior at low temperature, puncture and hail response, surface reflectance, and how a future repair or tie-in is made. {note}
+
+### Thermoplastic sheets are re-fusible, so a seam or repair made years after installation is the same weld as the original. Thermoset EPDM is vulcanized and cannot be re-fused, so its seams and repairs are made by adhesive or tape splice. Polymer-modified bitumen is a multi-ply system whose redundancy comes from stacking sheets rather than from sheet thickness. {note}
+
+### Where the roof will be exposed to grease, animal fat, or hydrocarbon discharge, membrane chemical resistance to those specific exposures becomes the governing selection criterion, because a membrane that performs well under weather exposure can soften or embrittle under a chemical one. {note}
+
+### Where a rooftop discharge or process exposure is identified in the Contract Documents, the Contractor shall submit the membrane manufacturer's published chemical resistance data for that exposure with the action submittal package.
+
+### The membrane material shall be as indicated in the datasheet.
+
+```datasheet
+label: Membrane Material
+type: radio
+options:
+ - "TPO — thermoplastic polyolefin sheet conforming to ASTM D6878"
+ - "PVC — polyvinyl chloride sheet conforming to ASTM D4434"
+ - "KEE — ketone ethylene ester sheet conforming to ASTM D6754"
+ - "EPDM — ethylene propylene diene terpolymer sheet conforming to ASTM D4637"
+ - "SBS polymer-modified bitumen sheet conforming to ASTM D6162, ASTM D6163, or ASTM D6164"
+ - "APP polymer-modified bitumen sheet conforming to ASTM D6222, ASTM D6223, or ASTM D6509"
+```
+
+### All membrane, flashing, adhesive, primer, sealant, and accessory products in the assembly shall come from a single membrane manufacturer's system or shall be confirmed in writing by that manufacturer as compatible with its system.
+
+### Two membrane families shall not be joined to each other in the field except through a transition detail published by the manufacturer of at least one of them or accepted by the Engineer of Record.
+
+### Where the roof area is divided among more than one membrane family, the boundary between them shall be at an expansion joint, an area divider, or a raised curb, and shall be [[drawing: as indicated on the roof plan]].
+
+## Single-Ply Membrane Thickness and Reinforcement {toc}
+
+### Sheet thickness is what remains between the reinforcement and the weather. Thicker sheet increases the coating thickness over the scrim, which is the material available to weather, to resist puncture, and to be welded or spliced without exposing the reinforcement. It does not change the assembly's uplift resistance, which is set by the attachment. {note}
+
+### Reinforcement determines how the sheet carries load between attachment points and how it behaves at a flashing. A scrim-reinforced sheet resists tearing and spans between fastener rows; a non-reinforced sheet elongates and conforms to complex geometry; a fleece-backed sheet presents a fabric face for adhesive contact and adds a cushioning layer over an irregular substrate. {note}
+
+### The nominal thickness of a single-ply membrane shall be as indicated in the datasheet.
+
+```datasheet
+label: Single-Ply Membrane Thickness
+type: range
+unit: mil
+drawing_ref: "roof assembly schedule"
+options:
+ min: 40
+ max: 90
+ setpoints: [40, 45, 50, 60, 72, 80, 90]
+default: deferred
+```
+
+### The membrane supplied shall meet the minimum overall thickness and the minimum thickness over the reinforcement required by the governing material specification for the membrane family selected.
+
+### The Contractor shall submit the manufacturer's published thickness over reinforcement for the specified product, and shall not substitute nominal overall thickness for that value.
+
+### Single-ply membrane reinforcement shall be as indicated in the datasheet.
+
+```datasheet
+label: Single-Ply Membrane Reinforcement
+type: radio
+options:
+ - "Non-reinforced sheet"
+ - "Internally scrim-reinforced sheet"
+ - "Fabric-backed sheet"
+ - "Fleece-backed sheet"
+ - "Not applicable to a polymer-modified bitumen membrane"
+```
+
+### Where the membrane is mechanically attached or induction-welded, the sheet shall be reinforced, because in those methods the sheet carries wind load in tension between attachment points.
+
+### Where the membrane thickness is not indicated in the datasheet, the Contractor shall request the value before ordering material rather than supplying the thinnest sheet the material specification permits.
+
+## Polymer-Modified Bitumen Membrane Build-Up {toc}
+
+### A polymer-modified bitumen roof gets its reliability from plies rather than from a single thick sheet. Each ply is fully bonded to the one below, so a defect in one ply is not a defect in the membrane, and the cap sheet carries the weathering surface while the base and interply sheets carry the redundancy. {note}
+
+### The number of polymer-modified bitumen plies shall be as indicated in the datasheet.
+
+```datasheet
+label: Polymer-Modified Bitumen Ply Count
+type: range
+unit: plies
+drawing_ref: "roof assembly schedule"
+options:
+ min: 1
+ max: 4
+ step: 1
+default: deferred
+```
+
+### Each polymer-modified bitumen ply shall conform to the material specification identified for the membrane material selected in the datasheet.
+
+### Base, interply, and cap sheets shall be products of one manufacturer and shall be listed together in the assembly relied on for uplift resistance and fire classification.
+
+### Each ply shall be fully bonded to the ply or substrate below it, with no unbonded area other than at a designed expansion or relief joint.
+
+### The cap sheet shall be installed on the same day the ply beneath it is installed, or the exposed ply shall be protected in accordance with the manufacturer's published requirements until the cap sheet is installed.
+
+## Membrane Surfacing {toc}
+
+### Surfacing performs three distinct functions that a project may want in different combinations: protecting the membrane from ultraviolet exposure, changing the surface's solar reflectance, and providing a wearing surface. Because a single-ply sheet already carries its own weathering surface, surfacing is an addition for those roofs and an integral part of the product for granule-surfaced bituminous cap sheets. {note}
+
+### Membrane surfacing shall be as indicated in the datasheet.
+
+```datasheet
+label: Membrane Surfacing
+type: radio
+options:
+ - "None — the membrane weathering surface is exposed as manufactured"
+ - "Factory-applied mineral granule surfacing"
+ - "Field-applied aluminum-pigmented bituminous coating"
+ - "Field-applied elastomeric or acrylic reflective coating"
+ - "Aggregate set in a bituminous flood coat"
+```
+
+### Field-applied coatings shall be confirmed by the membrane manufacturer as compatible with the membrane and shall be applied at the published coverage rate.
+
+### Field-applied coatings shall not be applied until the membrane installation is complete, tested, and accepted, so that a coating does not conceal a defect from inspection.
+
+### Where a field-applied coating is part of the warranted assembly, the coating manufacturer's requirements for surface preparation, cure, and recoat interval shall be included in the submitted assembly.
+
+## Surface Color and Solar Reflectance {toc}
+
+### Membrane surface color and the solar reflectance requirement are separate decisions. A project may need a specific color for aesthetic or municipal reasons without a reflectance requirement, and a reflectance requirement is satisfied by tested values rather than by the appearance of the sheet. {note}
+
+### A reflective roof surface lowers membrane service temperature and reduces cooling load; in heating-dominated climates the same surface forgoes the winter solar gain a dark surface provides, which is why the adopted energy code sets the requirement by climate zone rather than universally. {note}
+
+### The membrane surface color shall be as indicated in the datasheet.
+
+```datasheet
+label: Membrane Surface Color
+type: radio
+options:
+ - "White"
+ - "Light gray"
+ - "Tan or beige"
+ - "Black"
+ - "Colored mineral granule surfacing"
+```
+
+### The solar reflectance requirement applying to the roof surface shall be as indicated in the datasheet.
+
+```datasheet
+label: Membrane Solar Reflectance Requirement
+type: radio
+options:
+ - "No minimum solar reflectance required by the adopted code or by the Owner"
+ - "Initial and aged solar reflectance and thermal emittance per the adopted energy code"
+ - "Solar reflectance index per the adopted energy code"
+ - "Solar reflectance index exceeding the adopted energy code as required by the Owner or a rating program"
+```
+
+### Where a reflectance requirement is indicated, the Contractor shall submit CRRC-1 rated or manufacturer-published initial and aged solar reflectance and thermal emittance values for the specified product.
+
+### Where the specified membrane cannot meet an indicated reflectance requirement, the Contractor shall report the conflict before ordering material rather than after installation.
+
+# Thermoplastic Membrane Requirements {toc}
+
+## Scope of the Thermoplastic Article {toc}
+
+### Requirements in this article apply where TPO, PVC, or KEE is selected as the membrane material in the datasheet. {note}
+
+### Thermoplastic sheets are welded rather than glued: heat softens the sheet surfaces and pressure fuses them, producing a homogeneous joint whose strength is a property of the sheet rather than of an adhesive layer. A weld that is made correctly fails in the sheet body when peel-tested. {note}
+
+## Thermoplastic Seaming Method {toc}
+
+### All field seams, lap seams, and flashing seams in a thermoplastic membrane shall be hot-air welded.
+
+### Adhesive-bonded and tape-bonded seams shall not be used in a thermoplastic membrane except where the membrane manufacturer publishes a bonded detail for a specific condition that cannot be welded, and that detail is submitted and accepted.
+
+### Cut edges of a thermoplastic sheet that will remain exposed and are not captured by a weld shall be treated with the manufacturer's cut-edge sealant where the manufacturer requires it for the product.
+
+## Plasticizer and Bitumen Compatibility {toc}
+
+### Plasticizers give a PVC sheet its flexibility and are mobile: in sustained contact with bituminous materials they migrate out of the sheet, and the sheet stiffens and eventually cracks. The mechanism is a property of the contact, not of workmanship, so it is prevented by material selection rather than by care during installation. {note}
+
+### Where the membrane is PVC, every insulation facer, cover board, adhesive, sealant, and accessory in contact with the membrane shall be confirmed in writing by the membrane manufacturer as resistant to plasticizer migration.
+
+### Bituminous products shall not be placed in direct contact with a PVC membrane.
+
+### Where a PVC membrane is installed over an existing bituminous roof in a recover, a separation layer accepted by the membrane manufacturer shall be installed between the existing roof and the new membrane.
+
+### Where the membrane is KEE, the compatibility confirmation required above shall be obtained for the KEE product, because the polymer and its compatibility behavior differ from those of PVC.
+
+# Thermoset EPDM Membrane Requirements {toc}
+
+## Scope of the EPDM Article {toc}
+
+### Requirements in this article apply where EPDM is selected as the membrane material in the datasheet. {note}
+
+### EPDM is vulcanized, so its polymer chains are cross-linked and the sheet cannot be re-melted. Every seam and every repair is therefore a bonded joint whose strength depends on surface cleanliness, primer, and the pressure applied while the bond is formed. {note}
+
+### Because the joint is bonded rather than fused, EPDM seam bond strength develops over hours rather than instantly, and the seam is vulnerable to disturbance during that period. {note}
+
+## EPDM Seaming and Splicing {toc}
+
+### EPDM field seams and flashing seams shall be made with the manufacturer's seam tape and splice primer, or with the manufacturer's splice adhesive where the manufacturer's published detail calls for it.
+
+### The splice area shall be cleaned with the manufacturer's cleaner until the wiping cloth shows no residue, and shall be allowed to dry before primer is applied.
+
+### Splice primer shall be applied at the published coverage rate and shall be allowed to reach the published condition before tape or adhesive is applied.
+
+### Seam tape shall be applied continuously from one end of the splice to the other without lifting or repositioning.
+
+### Each completed splice shall be rolled with a steel roller across the full splice width, working from the center of the lap outward.
+
+### Completed EPDM seams shall be protected from foot traffic, standing water, and membrane strain for not less than 24 hours after the splice is made.
+
+### Field-cut EPDM edges that remain exposed shall be treated with the manufacturer's lap edge sealant.
+
+## EPDM Dimensional Movement {toc}
+
+### EPDM sheet undergoes measurable dimensional change over the temperature range a roof surface sees, and on assemblies where the sheet is not continuously bonded that movement accumulates as tension at the base flashings. Continuous adhesion of base flashings and a generous flashing lap onto the field membrane are what absorb it. {note}
+
+### EPDM base flashings shall be continuously adhered to the vertical substrate for their full height.
+
+### EPDM base flashings shall lap onto the field membrane not less than 6 inches, spliced in accordance with this article.
+
+### EPDM base flashings shall be mechanically terminated at the top of the flashing in addition to being adhered.
+
+# Polymer-Modified Bitumen Membrane Requirements {toc}
+
+## Scope of the Bituminous Article {toc}
+
+### Requirements in this article apply where SBS or APP polymer-modified bitumen is selected as the membrane material in the datasheet. {note}
+
+### SBS and APP describe the polymer used to modify the asphalt and, with it, the application methods the sheet supports. SBS sheets remain flexible at low temperature and are commonly set in hot asphalt, cold adhesive, or self-adhered; APP sheets carry a higher softening point and are commonly torch-applied. {note}
+
+## Bituminous Application Method Compatibility {toc}
+
+### Each polymer-modified bitumen ply shall be applied by a method the sheet manufacturer publishes for that sheet.
+
+### Hot asphalt shall be applied within the equiviscous temperature range published for the asphalt and shall not be heated above its published flash point at any time.
+
+### Asphalt kettle and tanker temperatures shall be recorded at intervals during application and the record shall be available to the Engineer of Record on request.
+
+### Torch application shall not be performed directly against combustible construction, over an unprotected combustible deck, or at a vertical surface where the flame cannot be controlled.
+
+### Where torch application is used, the Contractor shall maintain a fire watch during the work and for the period after the work that the Contract Documents or the Authority Having Jurisdiction require.
+
+### Cold-process adhesive shall be applied at the published coverage rate and shall be allowed the published set time before the sheet above is applied.
+
+### Self-adhered sheets shall be applied only within the surface temperature range the manufacturer publishes for the product, and the substrate shall be primed where the manufacturer requires priming.
+
+## Bituminous Ply Bonding {toc}
+
+### Each ply shall be rolled or broomed into the bonding medium immediately after placement so that full contact is achieved before the medium sets.
+
+### Bitumen shall flow slightly and continuously ahead of the roll at every lap, confirming that the lap is fully bonded across its width.
+
+### Voids, fishmouths, and unbonded laps shall be cut, reset, and patched with the same sheet before the following ply is installed.
+
+### Granule-surfaced sheet shall have the lap area of the granules embedded or the lap shall be made in the manufacturer's selvage edge, so that the bond is made to the sheet rather than to loose granules.
+
+# Roof Insulation {toc}
+
+## Insulation Material {toc}
+
+### The insulation layer answers to more than thermal resistance. It provides the substrate the membrane is attached to, contributes to the assembly's fire classification, carries the fastener that reaches the deck, and takes the compressive load of anything that walks or bears on the roof. Different materials trade these against each other. {note}
+
+### Foam plastic boards deliver the highest thermal resistance per inch. Mineral wool and cellular glass are noncombustible and dimensionally stable when wet. Perlite and cellulosic fiberboard tolerate hot asphalt. Lightweight insulating concrete provides slope and insulation in one operation on a structural deck. {note}
+
+### Roof insulation material shall be as indicated in the datasheet.
+
+```datasheet
+label: Roof Insulation Material
+type: checkbox
+options:
+ - "Polyisocyanurate board per ASTM C1289"
+ - "Expanded polystyrene board per ASTM C578"
+ - "Extruded polystyrene board per ASTM C578"
+ - "Mineral wool board per ASTM C726"
+ - "Cellular glass board per ASTM C552"
+ - "Perlite board per ASTM C728"
+ - "Cellulosic fiberboard per ASTM C208"
+ - "Lightweight insulating concrete fill"
+```
+
+### Insulation facers shall be compatible with the adhesive, bonding medium, and membrane in contact with them, and the compatibility shall be confirmed in writing by the membrane manufacturer.
+
+### Polystyrene insulation shall not be placed in direct contact with hot asphalt, solvent-based adhesive, or a torch flame; a separation layer or cover board accepted by the membrane manufacturer shall be installed between them.
+
+### Insulation boards shall be sized so that no board dimension at a roof edge, curb, or penetration is less than 16 inches, and shall be cut to fit tightly against adjoining construction.
+
+### Gaps between insulation boards wider than 1/4 inch shall be filled with insulation of the same material rather than left open or filled with sealant.
+
+### Insulation shall not be installed in a greater quantity than can be covered by the membrane during the same work period.
+
+## Insulation Thermal Resistance {toc}
+
+### Thermal resistance for a roof is set by the adopted energy code for the climate zone, adjusted by whatever the project targets beyond code. It is a project value rather than a product value, so it belongs to the design documents. {note}
+
+### For polyisocyanurate insulation, the value used for code compliance is the long-term thermal resistance the manufacturer publishes under ASTM C1289 rather than an initial or as-manufactured value, because the material's thermal resistance changes as the blowing agent equilibrates. {note}
+
+### The total thermal resistance of the roof insulation shall be as indicated in the datasheet.
+
+```datasheet
+label: Total Roof Insulation Thermal Resistance
+type: range
+unit: "h·ft²·°F/Btu"
+drawing_ref: "roof assembly schedule"
+options:
+ min: 0
+ max: 60
+ step: 1
+default: deferred
+```
+
+### The insulation supplied shall achieve the indicated thermal resistance using the published design value for the material, and the Contractor shall submit the calculation demonstrating this.
+
+### Where polyisocyanurate insulation is used, the long-term thermal resistance value published under ASTM C1289 shall be used in that calculation.
+
+### Where a tapered system is installed, the indicated thermal resistance shall be achieved at the thinnest point of the tapered field unless the Contract Documents state that it is an average value.
+
+## Insulation Layer Configuration {toc}
+
+### Board joints are the weak line in an insulation layer: they are where air moves through, where thermal bridging concentrates, and where a fastener plate sits on an unsupported edge. Installing the same total thickness in two or more layers with offset joints removes the continuous path through the layer. {note}
+
+### A single layer remains a real configuration — over a structural concrete deck, in a thin recover, or where the total thickness does not warrant a second board — which is why the layer count is a project decision rather than a fixed rule. {note}
+
+### The number of insulation layers shall be as indicated in the datasheet.
+
+```datasheet
+label: Number of Insulation Layers
+type: range
+unit: layers
+drawing_ref: "roof assembly schedule"
+options:
+ min: 1
+ max: 4
+ step: 1
+default: deferred
+```
+
+### Where insulation is installed in two or more layers, joints in each layer shall be offset from joints in the adjacent layer in both directions by not less than 6 inches.
+
+### Where insulation is installed in two or more layers, no joint shall align through the full thickness of the insulation.
+
+### Insulation boards shall be laid with joints tight and with the long dimension perpendicular to the steel deck flutes where the deck is a steel deck.
+
+### Insulation shall bear continuously on the deck or on the layer below, and shall not bridge over a deck flute, a deflection, or a change in plane.
+
+## Tapered Insulation {toc}
+
+### Tapered insulation is the usual way to obtain positive slope on a structure framed level. It is a designed system rather than a product: the board thicknesses, panel layout, cricket geometry, and drain sumps are derived from the drain locations and the required slope. {note}
+
+### Whether tapered insulation is used, and where, shall be as indicated in the datasheet.
+
+```datasheet
+label: Tapered Insulation
+type: radio
+options:
+ - "Not required — the structural framing provides the design slope"
+ - "Tapered insulation over the full roof area"
+ - "Tapered crickets and saddles at obstructions and drain sumps with field areas at structural slope"
+ - "Tapered insulation over the full roof area with crickets and saddles at obstructions"
+ - "Tapered lightweight insulating concrete fill"
+```
+
+### Where tapered insulation is indicated, the tapered layout shall be designed by the insulation manufacturer from the drain locations, roof geometry, and design slope shown on the Contract Documents.
+
+### The tapered layout drawings shall be submitted and accepted before tapered material is fabricated.
+
+### Tapered panels shall be marked or keyed to the accepted layout drawings so that each panel is installed in its designed position.
+
+### The Contractor shall not substitute panel thicknesses or alter the tapered layout in the field without the insulation manufacturer's revised design and the Engineer of Record's acceptance.
+
+### Where tapered insulation adds dead load beyond that carried in the structural design, the Contractor shall report the added load to the Engineer of Record before fabrication.
+
+# Cover Board {toc}
+
+## Cover Board Selection {toc}
+
+### A cover board is a separation and bearing layer between the insulation and the membrane. It gives adhesive a stable, non-absorbent surface to bond to, spreads foot and equipment loads over the softer insulation below, keeps insulation facers out of chemical contact with the membrane, and can raise the assembly's fire classification. {note}
+
+### Not every assembly needs one. A mechanically attached membrane over a rigid, high-density insulation facer transfers load through the fastener rather than through the board, and a recover over a sound existing roof already has a bearing surface. The board is therefore a project decision rather than a fixed requirement. {note}
+
+### The cover board shall be as indicated in the datasheet.
+
+```datasheet
+label: Cover Board Material
+type: radio
+options:
+ - "No cover board"
+ - "High-density polyisocyanurate cover board per ASTM C1289"
+ - "Glass-mat faced gypsum cover board per ASTM C1177"
+ - "Fiber-reinforced gypsum cover board per ASTM C1278"
+ - "Perlite cover board per ASTM C728"
+ - "Cellulosic fiberboard cover board per ASTM C208"
+ - "Mineral wool cover board per ASTM C726"
+ - "Asphaltic core cover board"
+```
+
+### The cover board thickness shall be as indicated in the datasheet.
+
+```datasheet
+label: Cover Board Thickness
+type: range
+unit: in
+drawing_ref: "roof assembly schedule"
+options:
+ min: 0.25
+ max: 1
+ setpoints: [0.25, 0.375, 0.5, 0.625, 0.75, 1]
+default: deferred
+```
+
+### The cover board specified shall appear in the assembly listing, classification, or test report relied on for uplift resistance and fire classification.
+
+### Where the membrane is adhered, the cover board shall be a product the membrane manufacturer publishes as an acceptable adhesive substrate for the specified adhesive.
+
+### Where a gypsum-based cover board is used, it shall be a product manufactured for exterior roofing exposure and shall be protected from precipitation until the membrane is installed over it.
+
+## Cover Board Installation {toc}
+
+### Cover board joints shall be offset from the joints in the insulation layer below by not less than 6 inches in both directions.
+
+### Cover boards shall be installed with joints tight, without gaps that leave the membrane unsupported.
+
+### Cover boards shall be attached by the method and at the density required by the assembly relied on for uplift resistance.
+
+### Cover board shall be installed only in the quantity that will be covered by membrane during the same work period, unless a temporary water cut-off protects it.
+
+# Vapor Retarder and Air Barrier Continuity {toc}
+
+## Vapor Retarder Determination {toc}
+
+### A vapor retarder below the insulation stops interior moisture from reaching the cold side of the assembly and condensing there. Whether that risk exists depends on the interior temperature and humidity the building will run at and the exterior conditions of the climate zone, which is a design analysis rather than a default. {note}
+
+### The same layer that solves a condensation problem creates one where it is not needed: a low-permeance layer directly on the deck traps incidental moisture that enters the assembly from above and prevents it from drying downward. Adding one as a precaution is therefore not a neutral act. {note}
+
+### Buildings with sustained high interior humidity — natatoriums, food processing, laundries, humidified manufacturing, and comparable occupancies — carry the highest condensation risk, and buildings with ordinary office, retail, and warehouse interiors carry the lowest, but the determination is made by analysis for the actual building rather than by occupancy label. {note}
+
+### The Engineer of Record shall determine whether a vapor retarder is required using a dew-point or hygrothermal analysis of the assembly under the building's design interior conditions and the climate zone's exterior conditions.
+
+### The vapor retarder class shall be as indicated in the datasheet.
+
+```datasheet
+label: Vapor Retarder Class
+type: radio
+options:
+ - "No vapor retarder"
+ - "Class I vapor retarder — 0.1 perm or less"
+ - "Class II vapor retarder — greater than 0.1 perm through 1.0 perm"
+ - "Class III vapor retarder — greater than 1.0 perm through 10 perm"
+```
+
+### Where the datasheet indicates no vapor retarder, the Contractor shall not install one on the Contractor's own initiative.
+
+## Vapor Retarder Materials and Installation {toc}
+
+### The vapor retarder material shall be as indicated in the datasheet.
+
+```datasheet
+label: Vapor Retarder Material
+type: radio
+options:
+ - "Not applicable — no vapor retarder in the assembly"
+ - "Self-adhering polymer-modified bituminous sheet"
+ - "Torch-applied or mopped polymer-modified bituminous sheet"
+ - "Mechanically fastened reinforced polyolefin sheet"
+ - "Loose-laid polyethylene film"
+ - "Fluid-applied vapor retarder membrane"
+ - "Foil facer on the base insulation layer serving as the vapor retarder"
+```
+
+### The vapor retarder shall be installed directly on the roof deck, below the insulation.
+
+### The vapor retarder shall be compatible with the deck, with the attachment method used for the insulation layer above it, and with the assembly relied on for uplift resistance.
+
+### Laps and end laps in a self-adhering vapor retarder shall be rolled to achieve full contact across the lap.
+
+### Penetrations through the vapor retarder shall be sealed with a compatible flashing sheet or tape before insulation is installed over them.
+
+### The vapor retarder shall be protected from foot traffic and from ultraviolet exposure and shall not be left exposed beyond the exposure period the manufacturer publishes.
+
+### Where the vapor retarder is fastened through the deck, the fastener pattern shall be that of the assembly relied on for uplift resistance.
+
+## Air Barrier Continuity at the Roof {toc}
+
+### The roof's air control layer is usually the vapor retarder or the membrane itself, and it has to connect to the wall's air barrier at the parapet or the roof-to-wall junction. An air barrier that stops at the top of the wall is not an air barrier. {note}
+
+### The roof air control layer shall be made continuous with the wall air barrier at every roof-to-wall and roof-to-parapet junction.
+
+### The transition detail between the roof air control layer and the wall air barrier shall be shown on the shop drawings and shall use materials each manufacturer confirms as compatible.
+
+### Air barrier materials, testing, and performance criteria are governed by [[sync/air-barriers]]; this standard governs the roof-side termination of the transition.
+
+# Membrane and Insulation Attachment {toc}
+
+## Attachment Method Selection {toc}
+
+### The attachment method decides how uplift load reaches the structure, and each route has consequences the others do not. A mechanically attached sheet carries load in tension and flutters between fastener rows under gusting. An adhered sheet distributes load over its full area and does not flutter, but depends on adhesive bond and cure conditions. A ballasted sheet resists uplift by weight, which places dead load on the structure and limits the slope. An induction-welded sheet is fastened below the membrane, so no fastener penetrates the finished sheet. {note}
+
+### Attachment also interacts with what is below it: fastened methods need a deck with a verified withdrawal value, adhered methods need a stable, non-absorbent substrate, and ballasted methods need a structure that can carry the ballast. {note}
+
+### The membrane attachment method shall be as indicated in the datasheet.
+
+```datasheet
+label: Membrane Attachment Method
+type: radio
+options:
+ - "Mechanically attached with fasteners and plates in the seam laps"
+ - "Mechanically attached with batten bars between seams"
+ - "Induction-welded to coated plates fastened through the substrate"
+ - "Adhered with field-applied bonding adhesive"
+ - "Adhered with factory-applied pressure-sensitive adhesive backing"
+ - "Adhered in hot asphalt"
+ - "Torch-applied to the substrate"
+ - "Adhered in cold-process bituminous adhesive"
+ - "Loose-laid and ballasted"
+```
+
+### The attachment method selected shall be the method used in the assembly relied on for uplift resistance.
+
+### Attachment methods shall not be mixed within one roof zone unless the assembly relied on for uplift resistance covers the mixed condition.
+
+### Where the field of the roof uses one attachment method and the perimeter and corner zones use an enhanced version of it, the enhancement shall be that required by the governing assembly and shall be shown on the shop drawings.
+
+## Mechanically Attached Membrane {toc}
+
+### In a mechanically attached system the fasteners sit within the seam lap, so the completed weld or splice covers them and the finished sheet is unpenetrated in the field. The lap therefore has to be wide enough to cover the plate and still deliver the full specified seam width beyond it. {note}
+
+### Fasteners and stress plates shall be installed within the seam lap at the spacing and row pattern required by the governing assembly.
+
+### Each stress plate shall seat flat on the membrane, fully bearing, without dishing the membrane or standing proud of it.
+
+### Fasteners shall be driven to the depth at which the plate is fully seated, and shall not be overdriven to the point of deforming the plate, tearing the membrane, or crushing the insulation below.
+
+### Fasteners installed with the plate tilted, the plate cracked, or the fastener stripped shall be removed, the opening patched, and the fastener reinstalled in sound material.
+
+### The seam lap shall extend beyond the edge of the stress plate by not less than the specified welded or spliced seam width.
+
+### Batten bars, where used, shall be installed continuously with the fastener spacing and end distance the governing assembly requires and shall be covered by a membrane strip welded or spliced to the field membrane.
+
+## Induction-Welded Membrane {toc}
+
+### Induction welding fastens coated plates through the membrane's substrate first, then bonds the membrane to those plates from above by induction heating, so the finished sheet has no fastener penetration and no fastener-driven seam layout. The bond is made at each plate and is verified plate by plate. {note}
+
+### Coated plates shall be installed at the pattern and density required by the governing assembly before the membrane is placed.
+
+### Each plate shall be bonded to the membrane by the induction welder at the machine setting and dwell time published for the membrane and plate combination.
+
+### Each bonded plate shall be weighted or magnetically clamped during cool-down for the period the equipment manufacturer publishes.
+
+### Bonds shall be verified by the method the membrane manufacturer publishes, and any plate that does not bond shall be re-welded or replaced.
+
+### Induction-welded plates and the induction welder shall be from the system the membrane manufacturer lists for the product, because bond depends on the plate coating and the machine setting together.
+
+## Adhered Membrane {toc}
+
+### Bonding adhesive develops its strength as solvent or water leaves the film. Rolling the sheet in while the film is still wet traps the carrier and produces a weak, slow-curing bond; rolling it in after the film has dried past its open time produces little bond at all. The correct condition is a repeatable field test rather than a clock reading, because it moves with temperature, humidity, and wind. {note}
+
+### Bonding adhesive shall be applied at the coverage rate published for the adhesive and the substrate.
+
+### Adhesive shall be applied to both the membrane and the substrate where the adhesive is formulated for two-sided application, and to the substrate alone where the adhesive is formulated for one-sided application.
+
+### Adhesive shall be allowed to reach the flash-off condition the manufacturer publishes before the membrane is rolled into it.
+
+### The Contractor shall verify the flash-off condition by hand test immediately before each section is rolled in.
+
+### The membrane shall be rolled with a weighted roller across its full width in both directions after placement, so that contact is achieved over the full adhered area.
+
+### Areas where the bond is suspect shall be probed, and any unbonded area found shall be cut open, re-adhered or patched, and re-verified.
+
+### Adhered membranes shall not be installed over a substrate that is damp, dusty, or contaminated, and the substrate shall be swept or vacuumed immediately before adhesive is applied.
+
+### Self-adhered membranes shall be applied only within the substrate temperature range the manufacturer publishes and shall be rolled immediately after placement.
+
+## Ballasted Membrane {toc}
+
+### Ballast resists uplift with weight, so its performance depends on the mass per unit area, the stone gradation or paver size, and the parapet height that keeps the ballast from scouring at the roof edge. Those variables are set by the ballasted-system design rather than chosen in the field. {note}
+
+### Ballast also puts a substantial permanent dead load on the structure and makes the membrane below it inaccessible for inspection, which is why the structural capacity and the Owner's maintenance expectations are both part of the decision. {note}
+
+### Ballasted assemblies shall be designed in accordance with ANSI/SPRI RP-4 and IBC Section 1504.5.
+
+### The ballast material shall be as indicated in the datasheet.
+
+```datasheet
+label: Ballast Material
+type: radio
+options:
+ - "Not applicable — the membrane is not ballasted"
+ - "Washed round river-run aggregate"
+ - "Crushed stone aggregate graded to the ballasted system design"
+ - "Concrete ballast pavers laid over the membrane"
+ - "Concrete pavers on pedestals over the membrane"
+ - "Aggregate ballast with concrete pavers at traffic areas"
+```
+
+### The ballast weight per unit area shall be as indicated in the datasheet.
+
+```datasheet
+label: Ballast Weight
+type: range
+unit: psf
+drawing_ref: "roof plan"
+options:
+ min: 0
+ max: 30
+ step: 1
+default: deferred
+```
+
+### A protection layer accepted by the membrane manufacturer shall be installed between the membrane and the ballast where the membrane manufacturer requires one for the ballast type specified.
+
+### Ballast gradation, weight, and the perimeter and corner enhancement shall match the ballasted system design relied on for uplift resistance.
+
+### The Structural Engineer of Record shall confirm in writing that the deck and framing carry the specified ballast dead load before ballast is placed.
+
+### The Contractor shall notify the Structural Engineer of Record in writing where the specified ballast loading differs from the loading shown in the structural documents.
+
+### Ballast shall be placed by a method that does not damage the membrane, and shall not be dropped or dumped directly onto an unprotected membrane.
+
+## Insulation and Cover Board Attachment {toc}
+
+### The insulation attachment carries the whole assembly's uplift load into the deck in every method except ballasting, so an under-applied adhesive ribbon or a short fastener limits the uplift resistance of the roof regardless of how well the membrane above it is attached. {note}
+
+### The insulation and cover board attachment method shall be as indicated in the datasheet.
+
+```datasheet
+label: Insulation and Cover Board Attachment Method
+type: radio
+options:
+ - "Mechanical fasteners and stress plates through the boards into the deck"
+ - "Low-rise polyurethane adhesive in ribbons"
+ - "Full-coverage insulation adhesive"
+ - "Hot asphalt mopping"
+ - "Factory-applied adhesive on self-adhered insulation"
+ - "Loose-laid under a ballasted assembly"
+ - "Mechanical fasteners in the base layer with adhesive in the layers above"
+```
+
+### Fasteners through insulation into the deck shall achieve the embedment the governing assembly requires for the deck type.
+
+### The Contractor shall calculate and verify fastener length against the total thickness of vapor retarder, insulation, cover board, and deck geometry before ordering fasteners.
+
+### Adhesive ribbons shall be applied at the bead width, bead spacing, and number of beads per board the governing assembly requires.
+
+### Boards set into adhesive shall be walked in or weighted until the adhesive has developed initial bond, and shall not be repositioned after the adhesive has begun to set.
+
+### Insulation shall not be loose-laid beneath a membrane that is mechanically attached or adhered, except where the governing assembly is a ballasted assembly.
+
+## Fasteners and Stress Plates {toc}
+
+### Roof fasteners live in the most corrosive part of the assembly: they pass through a layer that can hold condensation and they are unreachable for the life of the roof. Corrosion resistance is therefore specified rather than assumed. {note}
+
+### Fastener corrosion resistance shall be as indicated in the datasheet.
+
+```datasheet
+label: Fastener Corrosion Resistance
+type: radio
+options:
+ - "Coated carbon steel meeting the corrosion resistance requirements of FM 4470"
+ - "Austenitic stainless steel"
+ - "Coated carbon steel with supplemental coating for severe marine exposure"
+default: "Coated carbon steel meeting the corrosion resistance requirements of FM 4470"
+```
+
+### Fasteners in steel deck shall be self-drilling, self-tapping screws listed for the deck gauge in the governing assembly.
+
+### Fasteners in structural concrete, precast concrete, gypsum concrete, or lightweight insulating concrete shall be the type listed for that deck and shall achieve the withdrawal value the assembly requires.
+
+### Fasteners in wood decks shall be ring-shank or threaded roofing fasteners listed for wood substrates.
+
+### Stress plates shall be the diameter, shape, and material listed in the governing assembly, and shall not be substituted with a plate of different geometry.
+
+### Fasteners and stress plates from different manufacturers shall not be combined in one attachment unless the governing assembly lists that combination.
+
+# Membrane Seaming {toc}
+
+## Membrane Layout and Lap Orientation {toc}
+
+### A lap oriented across the slope collects water at its exposed edge for the life of the roof; a lap running with the slope sheds it. Where the roof geometry forces laps across the slope, shingling them downslope keeps water flowing over the joint rather than into it. {note}
+
+### Membrane sheets shall be laid out so that laps run parallel to the direction of slope wherever the roof geometry permits.
+
+### Where laps run across the slope, the upslope sheet shall lap over the downslope sheet.
+
+### End laps shall be staggered not less than 12 inches from end laps in adjacent sheet courses.
+
+### The membrane layout, including lap orientation and the location of every end lap, shall be shown on the shop drawings before installation begins.
+
+### Sheets shall be allowed to relax before seaming so that the sheet is not seamed under induced tension.
+
+## Hot-Air Welded Seams {toc}
+
+### Weld quality is set by three variables the operator controls together: temperature, speed, and pressure. A sound weld is verified by two independent means — a destructive peel test on a sample, which shows the failure mode, and a nondestructive probe of the production seam, which finds discontinuities. {note}
+
+### The minimum welded width of a machine-welded seam shall be as indicated in the datasheet.
+
+```datasheet
+label: Automatic Hot-Air Welded Seam Width
+type: range
+unit: in
+options:
+ min: 1
+ max: 3
+ step: 0.25
+default: 1.5
+```
+
+### The minimum welded width of a hand-welded seam shall be as indicated in the datasheet.
+
+```datasheet
+label: Hand-Welded Seam Width
+type: range
+unit: in
+options:
+ min: 0.75
+ max: 3
+ step: 0.25
+default: 1
+```
+
+### The welded width shall be measured on the completed seam after cooling, and shall be continuous for the full length of the seam.
+
+### Seam areas shall be cleaned of dirt, dust, and contamination immediately before welding.
+
+### Where a membrane surface has weathered beyond the period the manufacturer publishes for welding without preparation, the seam area shall be prepared by the manufacturer's published method before welding.
+
+### Intersections of a lap with an end lap shall be covered with a rounded or circular patch of the same membrane, welded continuously around its perimeter.
+
+### Patches at lap intersections shall have a corner radius of not less than 2 inches, so that the patch has no square corner to peel from.
+
+### No lap intersection shall be left without a patch on a completed roof.
+
+## Tape-Spliced and Adhesive-Spliced Seams {toc}
+
+### The minimum lap width of a tape-spliced or adhesive-spliced seam shall be as indicated in the datasheet.
+
+```datasheet
+label: Tape-Spliced Seam Lap Width
+type: range
+unit: in
+options:
+ min: 2
+ max: 6
+ step: 0.5
+default: 3
+```
+
+### Splice tape and splice adhesive shall be products of the membrane manufacturer for the membrane being spliced.
+
+### Lap sealant shall be applied to the exposed edge of a tape-spliced seam where the membrane manufacturer requires it for the product.
+
+### Splices shall not be made when the splice surfaces are below the minimum temperature published for the tape or adhesive.
+
+## Polymer-Modified Bitumen Laps {toc}
+
+### The minimum side lap width of a polymer-modified bitumen sheet shall be as indicated in the datasheet.
+
+```datasheet
+label: Polymer-Modified Bitumen Side Lap Width
+type: range
+unit: in
+options:
+ min: 2
+ max: 6
+ step: 0.5
+default: 3
+```
+
+### The minimum end lap width of a polymer-modified bitumen sheet shall be as indicated in the datasheet.
+
+```datasheet
+label: Polymer-Modified Bitumen End Lap Width
+type: range
+unit: in
+options:
+ min: 4
+ max: 12
+ step: 1
+default: 6
+```
+
+### End laps in successive plies shall be staggered so that end laps do not align through the membrane thickness.
+
+### Laps shall be pressed or rolled while the bonding medium is fluid so that bitumen flows continuously at the lap edge.
+
+### Excess bitumen at a lap edge shall be struck smooth rather than left as a ridge that will collect debris.
+
+# Flashings and Terminations {toc}
+
+## Base Flashing {toc}
+
+### Flashings are where membrane roofs leak. A field seam is a straight, repeatable joint made by a machine on a flat plane; a flashing is a three-dimensional transition assembled by hand around an object, often after the trades that own that object have finished. The difference in failure rate follows from the difference in geometry, not from the difference in materials. {note}
+
+### Base flashing height is measured from the finished roof surface, which is the membrane plus any surfacing or ballast above it. Enough height keeps the flashing termination above the water line that debris damming, snow accumulation, and localized ponding produce at the base of a vertical surface. {note}
+
+### The minimum base flashing height above the finished roof surface shall be as indicated in the datasheet.
+
+```datasheet
+label: Minimum Base Flashing Height Above Finished Roof Surface
+type: range
+unit: in
+options:
+ min: 0
+ max: 24
+ step: 1
+default: 8
+```
+
+### Base flashing shall be the same membrane material as the field membrane or a flashing sheet the membrane manufacturer publishes as compatible with it.
+
+### Base flashing shall be continuously bonded to the vertical substrate for its full height.
+
+### Base flashing shall be joined to the field membrane by the same seaming method used for the field seams of that membrane family.
+
+### Base flashing shall be mechanically terminated at its top edge.
+
+### Where the height of an existing parapet, curb, or wall is less than the height indicated in the datasheet, the Engineer of Record shall direct an alternative termination detail, and the Contractor shall install the flashing to the greatest height the construction allows until that direction is issued.
+
+### Base flashing shall not bridge across a change in plane; it shall be pressed into every corner and reentrant angle so that the flashing bears on the substrate throughout.
+
+## Cants and Plane Transitions {toc}
+
+### A membrane bent through a square inside corner is stressed at a line rather than over an area, and a stiff sheet will bridge the corner rather than follow it. A cant or tapered edge strip converts the 90-degree bend into two shallower ones. {note}
+
+### The treatment at horizontal-to-vertical transitions shall be as indicated in the datasheet.
+
+```datasheet
+label: Horizontal-to-Vertical Transition Treatment
+type: radio
+options:
+ - "No cant strip"
+ - "45-degree cant strip at horizontal-to-vertical transitions"
+ - "Tapered insulation edge strip at horizontal-to-vertical transitions"
+```
+
+### Where a cant strip is indicated, it shall be not less than 3 inches on each face and shall be continuous along the transition.
+
+### Cant strips and tapered edge strips shall be of a material the assembly relied on for fire classification permits.
+
+### Cant strips shall be secured so that they do not shift while the flashing is installed over them.
+
+### Where the datasheet indicates no cant strip, the flashing shall still be pressed fully into the corner and shall not bridge it.
+
+## Wall and Parapet Terminations {toc}
+
+### A termination bar on a horizontal surface holds water against the top edge of the flashing and directs it behind the membrane, which is the opposite of what the bar is for. The bar belongs on a vertical face, with the horizontal surface above it covered by metal that sheds outward. {note}
+
+### Termination bars shall be installed on vertical surfaces.
+
+### Termination bars shall not be installed on a horizontal or upward-facing surface.
+
+### The termination bar material shall be as indicated in the datasheet.
+
+```datasheet
+label: Termination Bar Material
+type: radio
+options:
+ - "Extruded aluminum bar"
+ - "Stainless steel bar"
+ - "Galvanized steel bar"
+default: "Extruded aluminum bar"
+```
+
+### Termination bars shall be not less than 1/8 inch thick and shall be installed continuously along the top of the flashing.
+
+### The termination bar fastener spacing shall be as indicated in the datasheet.
+
+```datasheet
+label: Termination Bar Fastener Spacing
+type: range
+unit: in o.c.
+options:
+ min: 4
+ max: 24
+ step: 2
+default: 12
+```
+
+### Termination bar fasteners shall be set not more than 6 inches from each end of each bar length and at each bar splice.
+
+### Sealant shall be applied along the top edge of the termination bar and into each fastener penetration.
+
+### At a parapet, the base flashing shall terminate on the vertical inside face and the top of the parapet shall be covered by the coping, which is a separate assembly from the base flashing.
+
+### At a wall that receives cladding, the base flashing shall be terminated before the cladding is installed, and the cladding or its flashing shall lap over the top of the base flashing by not less than 2 inches.
+
+### Where a through-wall flashing is present, the roof base flashing shall be lapped under the through-wall flashing so that water leaving the wall is directed onto the roof membrane; through-wall flashing is governed by [[sync/through-wall-flashing]].
+
+## Penetration Flashing {toc}
+
+### A penetration flashing has to accommodate movement the membrane does not have: thermal cycling of a pipe, vibration of a duct or conduit, and differential settlement between the structure and whatever passes through it. A rigid seal at a moving penetration is a scheduled failure. {note}
+
+### A sealant-filled pitch pocket seals with a material that shrinks, weathers, and needs periodic refilling, so it makes the Owner's maintenance program part of the detail's performance. It remains the practical answer for clustered or irregular penetrations that cannot be individually booted. {note}
+
+### Every penetration through the roof membrane shall be flashed so that the membrane is sealed to the penetration and remains sealed through the movement the penetration undergoes.
+
+### The pipe penetration flashing method shall be as indicated in the datasheet.
+
+```datasheet
+label: Pipe Penetration Flashing Method
+type: radio
+options:
+ - "Prefabricated membrane boot heat-welded or spliced to the field membrane"
+ - "Field-fabricated membrane boot with a target patch and draw band"
+ - "Prefabricated split boot for penetrations that cannot be sleeved"
+ - "Sealant-filled pitch pocket"
+ - "Curbed and sleeved penetration with membrane flashing"
+```
+
+### Boots shall be secured to the penetration with a stainless steel draw band and sealed at the top of the boot with the manufacturer's sealant.
+
+### Penetrations spaced closely together shall be individually flashed where the spacing permits a boot on each.
+
+### Where penetrations are too closely spaced to be individually flashed, they shall be curbed together and the curb shall be flashed as a curb.
+
+### Sealant-filled pitch pockets shall be filled with a two-part pourable sealer, shall be crowned to shed water, and shall be topped off after the sealer has cured.
+
+### Every sealant-filled pitch pocket shall be identified on the record drawings and in the Owner's maintenance instructions.
+
+### Penetrations installed after the membrane is complete shall be flashed by the roofing Contractor using the same details, and shall not be sealed with caulk applied over the membrane.
+
+## Equipment Curbs and Rooftop Supports {toc}
+
+### A support leg bearing directly on the membrane concentrates load on a small area of insulation, compressing it and creating a depression that ponds water and strains the membrane at the edge of the bearing. Distributing the load over a pad is what keeps contact pressure within what the assembly can take. {note}
+
+### Rooftop equipment shall be set on curbs that raise the equipment base above the finished roof surface by not less than the base flashing height indicated in the datasheet.
+
+### Curbs shall be rigid, continuously supported by the structure, and shall not deflect under the equipment they carry.
+
+### The membrane flashing shall be carried up the curb and over its top, and shall be secured under the equipment base or under a metal counterflashing.
+
+### Curb flashing shall be terminated mechanically at the top of the curb rather than relying on the equipment base for securement.
+
+### Supports for piping, conduit, ductwork, and equipment that bear on the roof shall bear on pads that distribute the load so that contact pressure stays within the limit the membrane manufacturer publishes.
+
+### Support pads shall be a material the membrane manufacturer publishes as compatible with the membrane and shall be bonded to the membrane or set on a bonded protection layer.
+
+### Equipment supports shall not be attached to the membrane by fasteners driven through the finished membrane.
+
+## Roof Drain and Scupper Interfaces {toc}
+
+### The clamping ring at a roof drain is the seal, and it works by compressing the membrane evenly between the ring and the drain flange. A sump around the drain lowers the water depth at which the drain begins to work and keeps the seal below the surrounding roof plane. {note}
+
+### The membrane shall be carried into the drain and clamped between the drain flange and the clamping ring.
+
+### The membrane shall be continuously bonded to the drain flange with an adhesive or sealant compatible with the membrane before the clamping ring is set.
+
+### Clamping ring bolts shall be tightened evenly in sequence to the value the drain manufacturer publishes, without cutting or crushing the membrane.
+
+### A sump shall be formed in the insulation around each drain, extending not less than 12 inches from the drain body in every direction and recessed below the surrounding insulation surface.
+
+### Insulation within the sump shall be tapered rather than stepped, so that the membrane is continuously supported into the drain.
+
+### Scupper openings shall be cut cleanly through the parapet and the opening shall be made smooth before flashing.
+
+### The membrane flashing at a scupper shall extend onto the field membrane not less than 6 inches beyond the opening on all sides and shall be continuously bonded.
+
+### Scupper liners shall be set in a sealant compatible with the membrane, and the membrane flashing shall be bonded over the liner flange.
+
+### The secondary drainage inlet elevation shall be set so that the secondary system activates only after the primary system is obstructed, in accordance with IBC Section 1502.2.
+
+### Drain bodies, strainers, and storm piping are governed by [[sync/roof-drainage]]; this standard governs the membrane termination at them.
+
+## Expansion and Area Divider Joints {toc}
+
+### An expansion joint in the structure has to be reproduced in the roof, because a membrane bridged across a moving joint will tear at the line of movement. An area divider does the same job for thermal movement in a long, uninterrupted membrane run that has no structural joint under it. {note}
+
+### Structural expansion joints shall be carried through the roof assembly with a raised curbed expansion joint detail.
+
+### Expansion joint curbs shall be raised to not less than the base flashing height indicated in the datasheet on each side of the joint.
+
+### The membrane shall be flashed up each expansion joint curb and terminated on the curb; the joint itself shall be bridged by a manufactured expansion joint cover or a bellows detail published by the membrane manufacturer.
+
+### The membrane shall not be carried continuously across a structural expansion joint.
+
+### Area dividers, where used, shall be raised curbs flashed on both sides in the same manner as an expansion joint curb, and shall be located [[drawing: as indicated on the roof plan]].
+
+## Perimeter Edge Metal and Membrane Termination {toc}
+
+### The membrane shall be secured under the edge metal cleat, hook strip, or integral flange, and shall not be left as a free edge at the roof perimeter.
+
+### The membrane shall be sealed to the edge metal flange by the stripping ply, cover strip, or bonded lap detail the membrane manufacturer publishes for the membrane family in use.
+
+### Edge metal flanges that receive a membrane stripping ply shall be primed where the membrane manufacturer requires priming for the metal.
+
+### Edge metal joints shall be detailed to accommodate thermal movement, and the stripping over a joint shall accommodate that movement without tearing.
+
+### Edge metal shall be installed at the fastener type, spacing, and anchorage of the ES-1 tested configuration relied on for the perimeter edge classification.
+
+# Traffic Protection and Surfacing Installation {toc}
+
+## Walkway Protection {toc}
+
+### Walkway protection separates maintenance traffic from the membrane and gives a visible route that keeps that traffic off the rest of the roof. It also provides slip resistance on a wet membrane surface, which a bare sheet does not. {note}
+
+### Walkway protection shall be as indicated in the datasheet.
+
+```datasheet
+label: Walkway Protection
+type: radio
+options:
+ - "No walkway protection"
+ - "Membrane-compatible walkway pads bonded to the field membrane"
+ - "Extruded or molded rubber walkway pads"
+ - "Coated fabric walkway rolls"
+ - "Concrete or composite pavers set on pedestals"
+```
+
+### Where walkway protection is indicated, it shall be installed at roof access points, along the route between access points and serviceable equipment, and around equipment requiring periodic service.
+
+### Walkway protection shall be bonded to the field membrane by the same method used for the field seams of that membrane family, or shall be set on pedestals that bear on a bonded protection layer.
+
+### Walkway protection shall not be loose-laid on the membrane.
+
+### Walkway units shall be installed with a gap between adjacent units so that water drains between them rather than being impounded behind them.
+
+### Walkway protection shall not be installed over a seam, a lap intersection, or a flashing termination.
+
+## Ballast and Surfacing Placement {toc}
+
+### Aggregate ballast shall be placed uniformly to the weight per unit area indicated in the datasheet, verified by area and quantity rather than by appearance.
+
+### Ballast at the perimeter and corner zones shall be placed at the increased weight, gradation, or paver substitution the ballasted system design requires.
+
+### Aggregate set in a bituminous flood coat shall be embedded while the flood coat is fluid and the excess shall be removed after the coat has set.
+
+### Field-applied coatings shall be applied at the published coverage rate in the number of coats the manufacturer requires, with the published recoat interval observed between coats.
+
+### Coating shall not be applied over standing water, dew, or a surface that has not been cleaned by the method the coating manufacturer publishes.
+
+## Protection of Completed Work {toc}
+
+### The Contractor shall protect completed membrane work from damage by subsequent roofing operations and by other trades.
+
+### The membrane shall not be used as a work surface or a staging area without protection board laid over it.
+
+### Materials, equipment, and staging shall not be placed on the membrane without load distribution that keeps contact pressure within the limit the membrane manufacturer publishes.
+
+### Hot work, grinding, and cutting shall not be performed on or adjacent to the installed membrane without a fire watch and a noncombustible shield over the membrane.
+
+### Solvents, fuels, oils, and cleaning chemicals shall not be stored or decanted on the membrane.
+
+### Damage to completed membrane work shall be reported by the Contractor and repaired using the manufacturer's published repair detail before the damaged area is concealed.
+
+### Each repair shall be recorded on the record drawings with its location and the date of repair.
+
+# Testing and Inspection {toc}
+
+## Seam Verification {toc}
+
+### Probing a cooled seam with a rounded tool finds the discontinuity that a visual inspection cannot: a weld that looks continuous can have a void where the machine lifted, stalled, or ran cool. The probe is nondestructive, so it can be run on 100 percent of the production seam rather than on a sample. {note}
+
+### Every field seam, lap seam, and flashing seam shall be probed with a rounded-tip seam probe after the seam has cooled.
+
+### Seam probing shall be performed by the installing operator for each seam on the day the seam is made.
+
+### The roofing foreman shall independently probe not less than 10 percent of the seams made each day.
+
+### A location where the probe enters the seam shall be marked, recorded, and repaired.
+
+### Seam repairs shall be made by cleaning, preparing, and re-welding or re-splicing the affected length plus not less than 6 inches beyond the defect in each direction.
+
+### A defect that cannot be repaired before the end of the work period shall be temporarily sealed with a compatible tape or patch and shall be permanently repaired at the start of the next work period.
+
+### Where the foreman's probe results differ materially from the operator's results for the same seams, the Contractor shall stop production seaming and shall re-verify welder settings before resuming.
+
+## Fastener Withdrawal Testing {toc}
+
+### Published withdrawal values assume a deck in the condition it left the mill. On an existing deck, corrosion, prior fastener holes, and unknown gauge can all reduce the actual value, and the attachment pattern derived from a published table can then be wrong in a way no inspection would reveal. {note}
+
+### Whether fastener withdrawal testing is performed shall be as indicated in the datasheet.
+
+```datasheet
+label: Fastener Withdrawal Testing
+type: radio
+options:
+ - "Withdrawal testing per ANSI/SPRI FX-1 before the attachment pattern is finalized"
+ - "No withdrawal testing — attachment values taken from published deck tables"
+```
+
+### Where withdrawal testing is indicated, tests shall be performed in accordance with ANSI/SPRI FX-1 at representative locations distributed across the roof areas within the work.
+
+### Test locations shall include each distinct deck type, gauge, and condition present in the work.
+
+### Test results shall be submitted with the proposed attachment pattern before the pattern is finalized.
+
+### Where measured withdrawal values are below those assumed in the attachment design, the Contractor shall submit a revised attachment pattern based on the measured values for the Engineer of Record's acceptance.
+
+### Test penetrations shall be sealed and, where they occur in an area already covered, patched with the membrane manufacturer's published repair detail.
+
+## Post-Installation Leak Testing {toc}
+
+### The available test methods answer different questions. A flood test proves watertightness of a bounded area under a static head but loads the structure and cannot be used everywhere. Electronic leak detection locates breaches without loading the structure and can survey large areas, but needs a conductive substrate below the membrane and a membrane that is not electrically bridged by wet debris. An infrared survey finds trapped moisture rather than a breach, so it answers where water already is rather than where it entered. {note}
+
+### Post-installation leak testing shall be as indicated in the datasheet.
+
+```datasheet
+label: Post-Installation Leak Testing
+type: checkbox
+options:
+ - "Flood testing per ASTM D5957"
+ - "Low-voltage electronic leak detection per ASTM D7877"
+ - "High-voltage electronic leak detection per ASTM D7877"
+ - "Infrared thermographic moisture survey per ASTM C1153"
+ - "Verification core cuts at the frequency directed by the Engineer of Record"
+ - "Documented visual inspection of all seams, flashings, and terminations"
+default:
+ - "Documented visual inspection of all seams, flashings, and terminations"
+```
+
+### Where flood testing is indicated, the test duration shall be as indicated in the datasheet.
+
+```datasheet
+label: Flood Test Duration
+type: range
+unit: h
+options:
+ min: 2
+ max: 72
+ step: 1
+default: 24
+```
+
+### Flood test water depth shall be not less than 1 inch over the high point of the area under test and shall not exceed the depth the structure is designed to carry.
+
+### The Structural Engineer of Record shall confirm in writing that the structure carries the flood test load before any area is flooded.
+
+### The area below a flooded area shall be observed for leakage during the test and at the end of the test period.
+
+### On completion of a flood test, drains shall be unblocked and the area shall be allowed to drain fully before any further work proceeds on it.
+
+### Where electronic leak detection is indicated, the survey shall be performed in accordance with ASTM D7877 by an operator trained in the method used, and the survey report shall record the method, the equipment, and the location of every indication.
+
+### Every leak or breach located by testing shall be repaired by the membrane manufacturer's published repair detail and the repaired area shall be re-tested by the same method.
+
+### The cost of retesting after a failed test shall be borne by the Contractor.
+
+## Verification Core Cuts {toc}
+
+### A core cut is the only way to confirm that what is under the membrane matches what was submitted: layer count, board thickness, fastener pattern, and whether the substrate is dry. It is destructive, so its frequency is a judgment about how much verification the project wants. {note}
+
+### Where verification core cuts are indicated, they shall be taken at the frequency and at the locations the Engineer of Record directs.
+
+### Each core cut shall extend through the membrane, cover board, and insulation to the deck, and shall be large enough to identify each layer and its thickness.
+
+### The Contractor shall record for each core the layer sequence, the thickness of each layer, the fastener pattern observed, and the moisture condition of the substrate.
+
+### Each core cut shall be patched on the day it is taken using the membrane manufacturer's published repair detail.
+
+### Core cut locations shall be recorded on the record drawings.
+
+### Where a core cut reveals wet material, a layer sequence differing from the accepted submittal, or an attachment pattern differing from the governing assembly, the Contractor shall stop work in the affected area and shall not proceed until the discrepancy is resolved with the Engineer of Record.
+
+### Where a core cut reveals a condition that does not conform to the accepted submittal, the cost of additional investigative cores in the affected area shall be borne by the Contractor.
+
+## Final Inspection and Punch List {toc}
+
+### A final inspection shall be performed with the Contractor, the Engineer of Record, and, where manufacturer field representation is specified, the membrane manufacturer's representative in attendance.
+
+### The final inspection shall verify that seams are probed and documented, flashings are complete and terminated, penetrations are flashed, edge metal is installed and sealed, walkway protection is installed where indicated, drains and scuppers are clear, and no membrane edge is left unterminated.
+
+### The inspecting parties shall issue a written report identifying each item requiring correction.
+
+### The Contractor shall correct each identified item and shall notify the inspecting parties in writing when corrections are complete.
+
+### A follow-up inspection shall confirm that each item is resolved before warranty documents are executed.
+
+# Delivery, Storage, and Handling {toc}
+
+## Delivery and Product Protection {toc}
+
+### Membrane, insulation, and accessories shall be delivered in the manufacturer's original packaging with labels intact.
+
+### Materials shall be stored off the ground on pallets and shall be covered with a breathable, waterproof cover that is secured against wind.
+
+### Insulation and cover board shall be stored so that they remain dry, and any material that becomes wet shall be removed from the site.
+
+### Adhesives, primers, sealants, and coatings shall be stored within the temperature range the manufacturer publishes for storage.
+
+### Membrane rolls shall be stored on end or on their sides in accordance with the manufacturer's published instruction, and shall not be stacked beyond the height the manufacturer permits.
+
+### Materials shall be handled so that membrane rolls are not dropped on their ends and insulation boards are not damaged at their edges.
+
+## Rooftop Storage and Loading {toc}
+
+### Materials staged on a roof are a concentrated live load on a structure designed for a distributed one, and the concentration is highest at exactly the moment the assembly is least complete. {note}
+
+### Materials shall be distributed on the roof so that no concentrated load exceeds the capacity of the deck and framing at that location.
+
+### The Contractor shall obtain the Structural Engineer of Record's written concurrence with the proposed rooftop staging loads before staging material on the roof.
+
+### Materials shall not be staged on completed membrane without protection board, and shall not be staged over an unsupported deck span.
+
+### Materials staged on the roof overnight shall be secured and covered against wind and precipitation.
+
+# Warranty {toc}
+
+## Contractor Workmanship Warranty {toc}
+
+### The Contractor's warranty covers what the manufacturer's does not: the quality of the installation itself, including work the manufacturer's system warranty excludes because it involves products the manufacturer did not supply. {note}
+
+### The Contractor shall provide a written warranty against defects in workmanship and against leaks attributable to the installation.
+
+### The Contractor workmanship warranty term shall be as indicated in the datasheet.
+
+```datasheet
+label: Contractor Workmanship Warranty Term
+type: range
+unit: years
+options:
+ min: 1
+ max: 10
+ step: 1
+default: 2
+```
+
+### The Contractor warranty shall run from the date of substantial completion.
+
+### The Contractor warranty shall cover the labor and materials required to correct the defect and to repair damage the defect caused to the roof assembly.
+
+### The Contractor warranty shall be in addition to, and shall not be reduced by, the manufacturer's warranty.
+
+### Where a warranty repair is performed, the repaired work shall carry a fresh warranty term running from the date of the repair, or the remainder of the original term, whichever is longer.
+
+## Manufacturer System Warranty {toc}
+
+### The types differ in what they pay for. A material warranty pays for replacement sheet, usually prorated, and leaves the labor to the Owner. A dollar-limit system warranty pays labor and materials up to a stated cap, which is reached soonest on the large repair. A no-dollar-limit warranty removes the cap for qualifying leaks and, because the manufacturer then carries the labor exposure, is typically conditioned on authorized installation, specified detailing, and a manufacturer inspection before issuance. {note}
+
+### Those conditions are why warranty type is not a closeout decision. A project that selects a no-dollar-limit warranty after the membrane is installed may find that a thickness, a detail, or an installer qualification decided months earlier disqualifies it. {note}
+
+### The membrane manufacturer's warranty type shall be as indicated in the datasheet.
+
+```datasheet
+label: Manufacturer Warranty Type
+type: radio
+options:
+ - "No manufacturer system warranty beyond the material warranty furnished with the product"
+ - "Manufacturer material warranty covering membrane materials on a prorated basis"
+ - "Manufacturer system warranty covering labor and materials up to a stated dollar limit"
+ - "Manufacturer no-dollar-limit system warranty covering labor and materials"
+```
+
+### The membrane manufacturer's warranty term shall be as indicated in the datasheet.
+
+```datasheet
+label: Manufacturer Warranty Term
+type: range
+unit: years
+options:
+ min: 5
+ max: 35
+ setpoints: [5, 10, 12, 15, 20, 25, 30, 35]
+```
+
+### The peak gust wind speed covered by the manufacturer's warranty shall be as indicated in the datasheet.
+
+```datasheet
+label: Manufacturer Warranty Wind Speed Coverage
+type: range
+unit: mph
+options:
+ min: 0
+ max: 150
+ setpoints: [0, 55, 72, 80, 90, 100, 120, 150]
+```
+
+### The scope of assembly components covered by the manufacturer's warranty shall be as indicated in the datasheet.
+
+```datasheet
+label: Manufacturer Warranty Coverage Scope
+type: checkbox
+options:
+ - "Membrane sheet and manufacturer-supplied seam materials"
+ - "Flashing and penetration accessories supplied by the membrane manufacturer"
+ - "Cover board"
+ - "Roof insulation"
+ - "Vapor retarder"
+ - "Perimeter edge metal and coping"
+ - "Rooftop walkway protection"
+default:
+ - "Membrane sheet and manufacturer-supplied seam materials"
+ - "Flashing and penetration accessories supplied by the membrane manufacturer"
+```
+
+### The Contractor shall confirm with the membrane manufacturer, before the action submittal package is submitted, every condition the manufacturer places on issuing the warranty type and term indicated in the datasheet.
+
+### The Contractor shall report in writing, with the action submittal package, any project condition that would prevent issuance of the indicated warranty.
+
+### The Contractor shall not substitute a warranty of lesser type, shorter term, or narrower coverage scope than that indicated in the datasheet without the Owner's written acceptance.
+
+## Conditions Affecting Warranty Coverage {toc}
+
+### Most warranty disputes are about what happened to the roof after acceptance rather than about how it was built, which is why the exclusions have to reach the Owner as an operating instruction rather than as a document filed at closeout. {note}
+
+### The Contractor shall deliver to the Owner, with the warranty, a written statement of the conditions that void or limit coverage under the issued warranty.
+
+### The Contractor shall include in that statement the procedure by which the Owner obtains the manufacturer's authorization before any rooftop work is performed after acceptance.
+
+### Rooftop equipment shall be installed so that condensate, exhaust, and process discharge are routed to drainage rather than discharged onto the membrane surface.
+
+### Where a rooftop discharge onto the membrane cannot be avoided, a splash pad or protection layer compatible with the membrane shall be installed at the discharge point.
+
+### Where the roof will be exposed to chemical discharge, the membrane's resistance to that chemical shall be confirmed in writing by the membrane manufacturer before the discharge is placed in service.
+
+# Spare Materials and Owner Turnover {toc}
+
+## Spare Stock {toc}
+
+### Spare stock matters most for a membrane whose color and formulation change over a warranty term: a repair made in year twelve from the original roll is a better match, mechanically and visually, than one made from current production. {note}
+
+### Spare stock shall be as indicated in the datasheet.
+
+```datasheet
+label: Spare Stock Furnished to the Owner
+type: checkbox
+options:
+ - "Membrane sheet stock matching the installed membrane"
+ - "Seam tape, splice primer, and lap sealant"
+ - "Bonding adhesive"
+ - "Walkway protection matching the installed type"
+ - "Fasteners and stress plates"
+ - "Insulation and cover board"
+ - "Prefabricated flashing accessories"
+```
+
+### Spare stock shall be from the same production lot as the installed materials where the manufacturer can supply it from that lot.
+
+### Spare stock shall be delivered in the manufacturer's original packaging, labeled with the product designation, lot number, and the roof areas it matches.
+
+### Spare stock shall be delivered to the location on the site the Owner designates and shall be receipted by the Owner.
+
+### Spare stock with a published shelf life shall be labeled with its expiration date and the Owner shall be advised of that date at turnover.
+
+## Roof Maintenance Documentation {toc}
+
+### A membrane roof is a maintained asset, and the maintenance it needs is mostly inspection and debris removal at the places where water is directed and slowed. Without the record of where those places are, the Owner inspects the field and misses the drains, laps, and pitch pockets. {note}
+
+### The Contractor shall deliver written roof maintenance instructions covering the inspection frequency the membrane manufacturer publishes, the cleaning methods and materials the manufacturer permits, debris removal at drains and scuppers, and the items requiring periodic attention.
+
+### The maintenance instructions shall identify every sealant-filled pitch pocket, every field repair, and every location requiring periodic sealant renewal.
+
+### The maintenance instructions shall state the procedure for authorizing and executing rooftop work after acceptance so that warranty coverage is preserved.
+
+### The Contractor shall conduct a turnover walk with the Owner's maintenance personnel covering roof access, the walkway route, the drainage points, and the locations identified in the maintenance instructions.