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SynC · SynC Standards

Membrane Roofing

Rev7
IssuedAug 29, 2026
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1 Scope

1.1 Systems Covered

NOTE 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. (1.1.1)
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. (1.1.2)
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. (1.1.3)
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. (1.1.4)
1.1.5 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.
1.1.6 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.
1.1.7 The Contractor shall not proceed with a substituted assembly until the Engineer of Record has accepted that evidence in writing.

1.2 Work Excluded from This Standard

NOTE The following work is outside this standard and is governed elsewhere: (1.2.1)
  • Fluid-applied membranes and roof coating restoration systems — Fluid Applied RoofingFluid-Applied Roofing and CoatingsResolves to the current adopted revision.sync/fluid-applied-roofing
  • Sprayed polyurethane foam roofing
  • Vegetative roof assemblies, growing media, drainage layers, and plantings — Vegetated RoofingVegetated (Green) RoofingResolves to the current adopted revision.sync/vegetated-roofing
  • Discontinuous steep-slope roof coverings such as shingles, tile, slate, and standing-seam panels — Asphalt Shingle RoofingAsphalt Shingle RoofingResolves to the current adopted revision.sync/asphalt-shingle-roofing and Metal Roof PanelsMetal Roof PanelsResolves to the current adopted revision.sync/metal-roof-panels
  • Below-grade, plaza-deck, and split-slab waterproofing — Below Grade WaterproofingBelow-Grade WaterproofingResolves to the current adopted revision.sync/below-grade-waterproofing and Self Adhering Sheet WaterproofingSelf-Adhering Sheet WaterproofingResolves to the current adopted revision.sync/self-adhering-sheet-waterproofing
  • Roof drain body selection, leader sizing, and storm piping design — Roof DrainageRoof DrainageResolves to the current adopted revision.sync/roof-drainage
  • Architectural sheet metal fabrication, copings, and roof specialties beyond their interface with the membrane — Sheet Metal Flashing And TrimSheet Metal Flashing and TrimResolves to the current adopted revision.sync/sheet-metal-flashing-and-trim and Roof Specialties And CopingsRoof Specialties and CopingsResolves to the current adopted revision.sync/roof-specialties-and-copings
  • Structural design of the roof deck, its gauge, span, and attachment to the framing — Steel DeckSteel DeckResolves to the current adopted revision.sync/steel-deck
  • Roof hatches, smoke vents, and skylights as products — Roof Hatches And Smoke VentsRoof Hatches and Smoke VentsResolves to the current adopted revision.sync/roof-hatches-and-smoke-vents
  • Above-grade wall thermal insulation — Building Thermal InsulationBuilding Thermal InsulationResolves to the current adopted revision.sync/building-thermal-insulation
  • Whole-building air barrier design, of which the roof air barrier is one plane — Air BarriersAir BarriersResolves to the current adopted revision.sync/air-barriers

1.3 Roofing Work Type

NOTE 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. (1.3.1)
1.3.2 The type of roofing work shall be as indicated in the datasheet.
Roofing Work Typeradio
○ 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
1.3.3 Where the work is a recover, the Contractor shall verify and report the number of existing roof coverings in place before ordering materials.
1.3.4 A recover shall comply with the limits on additional roof coverings and on recover over existing construction in IBC Section 1511.
1.3.5 Where the existing roof system contains water-saturated insulation or a water-saturated substrate, the saturated material shall be removed rather than recovered.
1.3.6 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.

2 Referenced Standards

2.1 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.
2.2 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

3 Submittals

3.1 Action Submittals

NOTE 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. (3.1.1)
3.1.2 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
Action Submittals Requiredcheckbox
☑ 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
3.1.3 Product data submitted as a marked catalog page shall have the proposed product, thickness, and options clearly identified.

3.2 Informational Submittals

3.2.1 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
Informational Submittals Requiredcheckbox
☑ 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

3.3 Closeout Submittals

3.3.1 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
Closeout Submittals Requiredcheckbox
☑ 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
3.3.2 Record drawings shall be delivered in an editable electronic format as well as in the reproducible format the Contract Documents require for closeout.

4 Quality Assurance

4.1 Installer Qualifications

NOTE 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. (4.1.1)
4.1.2 The qualification basis for the roofing installer shall be as indicated in the datasheet.
Installer Qualification Basischeckbox
☑ 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
4.1.3 The Contractor shall submit evidence of each qualification indicated in the datasheet before the action submittal package is accepted.
4.1.4 Where manufacturer authorization is indicated, the authorization shall be current at the start of the work and shall be maintained through final acceptance.
4.1.5 The roofing foreman assigned to the project shall have not less than five years of documented field experience with the membrane family being installed.
4.1.6 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.

4.2 Welding and Torch Operator Qualification

NOTE 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. (4.2.1)
4.2.2 Each hot-air welding operator shall produce acceptable test welds on the project membrane before production welding begins.
4.2.3 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.
4.2.4 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.
4.2.5 Test weld results, including welder settings, shall be recorded and made available to the Engineer of Record on request.
4.2.6 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.

4.3 Pre-Installation Conference

4.3.1 A pre-installation conference shall be held before roofing work begins.
4.3.2 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.
4.3.3 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.
4.3.4 The Contractor shall record and distribute conference minutes within five business days of the conference.

4.4 Manufacturer Field Representation

NOTE 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. (4.4.1)
4.4.2 Manufacturer field representation shall be as indicated in the datasheet.
Manufacturer Field Representationcheckbox
☑ 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
4.4.3 Reports from each manufacturer site visit shall be included in the closeout submittal.
4.4.4 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.

4.5 Field Mock-Up

NOTE 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. (4.5.1)
4.5.2 Whether a field mock-up is required shall be as indicated in the datasheet.
Field Mock-Upradio
○ No mock-up required
○ Mock-up panel required before production installation
○ Mock-up panel required and retained as part of the finished work
4.5.3 Where a mock-up is required, it shall be not less than 100 square feet of the specified assembly built on the project deck.
4.5.4 The mock-up shall include at least one field seam, one lap intersection, one base flashing at a vertical surface, and one penetration flashing.
4.5.5 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.
4.5.6 The accepted mock-up shall establish the standard of workmanship for the remainder of the work.
4.5.7 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.

4.6 Product Identification and Labeling

4.6.1 Membrane rolls shall bear the manufacturer name, product designation, nominal thickness, and the governing material specification.
4.6.2 Insulation and cover boards shall bear the manufacturer name, the governing material specification, and the thermal resistance where the product is a thermal insulation.
4.6.3 Fastener and stress plate packaging shall identify the product designation and the deck types for which the fastener is listed.
4.6.4 Perimeter edge systems required to meet ANSI/SPRI ES-1 shall be labeled, tagged, or delivered with documentation identifying the tested classification.
4.6.5 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.

5 Environmental and Substrate Conditions

5.1 Ambient and Surface Temperature Limits

NOTE 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. (5.1.1)
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. (5.1.2)
5.1.3 The minimum ambient and substrate temperature at which installation may proceed shall be as indicated in the datasheet.
Minimum Ambient and Substrate Installation Temperaturerange
°F
-2060
5.1.4 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.
5.1.5 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.
5.1.6 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.
5.1.7 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.
5.1.8 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.

5.2 Precipitation and Surface Moisture

5.2.1 Membrane installation shall not proceed during rain, snow, sleet, or fog.
5.2.2 Membrane installation shall not proceed where the substrate carries standing water, frost, ice, dew, or condensate.
5.2.3 The Contractor shall remove all surface moisture from the substrate and shall confirm the substrate is dry immediately before each area is covered.
5.2.4 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.
5.2.5 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.
5.2.6 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.

5.3 Roof Deck Acceptance

NOTE 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. (5.3.1)
5.3.2 The roof deck type shall be as indicated in the datasheet.
Roof Deck Typeselect
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
Per drawings — structural drawings (deferred by default)
5.3.3 The Contractor shall inspect the deck for the full area of the work before installing any component of the assembly.
5.3.4 The Contractor shall report every deck deficiency in writing before covering the affected area.
5.3.5 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.
5.3.6 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.
5.3.7 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.
5.3.8 Wood decks shall be securely fastened, free of protruding fasteners, and free of decayed or delaminated material.
5.3.9 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.
5.3.10 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.
5.3.11 The Contractor shall not proceed over a deficient deck area until the deficiency has been corrected and the area re-inspected.
5.3.12 Where the parties disagree whether a deck condition is a deficiency, the Engineer of Record shall make the initial determination.

5.4 Existing Roof Survey

NOTE 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. (5.4.1)
5.4.2 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.
5.4.3 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.
5.4.4 Areas identified as wet by the survey shall be opened and verified by cut, and wet material shall be removed to sound, dry construction.
5.4.5 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.
5.4.6 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.

5.5 Roof Slope and Drainage

NOTE 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. (5.5.1)
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. (5.5.2)
5.5.3 The design roof slope to drainage shall be as indicated in the datasheet.
Design Roof Slope to Drainagerange
in./ft
06
Per drawings — roof plan (deferred by default)
5.5.4 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.
5.5.5 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.
5.5.6 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.
5.5.7 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.
5.5.8 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.
5.5.9 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.
5.5.10 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.
5.5.11 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 Roof DrainageRoof DrainageResolves to the current adopted revision.sync/roof-drainage.

6 Wind Uplift Design Basis

6.1 Design Uplift Pressures

NOTE 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. (6.1.1)
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. (6.1.2)
6.1.3 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.
Design Uplift Pressure — Field Zonerange
psf
0500
Per drawings — roof plan wind zone diagram (deferred by default)
Design Uplift Pressure — Perimeter Zonerange
psf
0500
Per drawings — roof plan wind zone diagram (deferred by default)
Design Uplift Pressure — Corner Zonerange
psf
0500
Per drawings — roof plan wind zone diagram (deferred by default)
6.1.4 The extent of the perimeter and corner zones shall be as indicated on the roof plan wind zone diagram.
6.1.5 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.

6.2 Assembly Uplift Resistance

NOTE 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. (6.2.1)
6.2.2 The basis on which the assembly's uplift resistance is established shall be as indicated in the datasheet.
Assembly Uplift Resistance Basisradio
○ 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
6.2.3 The listed, classified, or calculated uplift resistance of the assembly shall equal or exceed the design uplift pressure for each roof zone.
6.2.4 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.
6.2.5 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.
6.2.6 Nonballasted roof assemblies shall satisfy IBC Section 1504.4, and ballasted low-slope single-ply assemblies shall satisfy IBC Section 1504.5.

6.3 Zone Enhancement and Fastener Density

6.3.1 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.
6.3.2 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.
6.3.3 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.
6.3.4 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.
6.3.5 The Contractor shall verify the installed attachment pattern in each zone against the shop drawings before the pattern is concealed by the next layer.

6.4 Perimeter Edge Securement

NOTE 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. (6.4.1)
6.4.2 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.
6.4.3 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.
6.4.4 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.
6.4.5 Edge system fastener type, spacing, and substrate anchorage shall match the tested configuration on which the ES-1 classification is based.
6.4.6 Perimeter edge systems shall be furnished, fabricated, and finished in accordance with Roof Specialties And CopingsRoof Specialties and CopingsResolves to the current adopted revision.sync/roof-specialties-and-copings and Sheet Metal Flashing And TrimSheet Metal Flashing and TrimResolves to the current adopted revision.sync/sheet-metal-flashing-and-trim; this standard governs their interface with the membrane.

7 Fire Performance

7.1 Roof Covering Fire Classification

NOTE 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. (7.1.1)
7.1.2 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.
Roof Covering Fire Classificationradio
● 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
7.1.3 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.
7.1.4 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.
7.1.5 Where more than one deck type occurs within the scope of the work, a classified assembly shall be identified for each deck type.

7.2 Roof Deck Construction Fire Requirements

NOTE 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. (7.2.1)
7.2.2 The fire requirement applying to the roof deck construction shall be as indicated in the datasheet.
Roof Deck Construction Fire Requirementradio
○ 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
7.2.3 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.
7.2.4 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.

8 Membrane Selection

8.1 Membrane Material

NOTE 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. (8.1.1)
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. (8.1.2)
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. (8.1.3)
8.1.4 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.
8.1.5 The membrane material shall be as indicated in the datasheet.
Membrane Materialradio
○ 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
8.1.6 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.
8.1.7 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.
8.1.8 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 as indicated on the roof plan.

8.2 Single-Ply Membrane Thickness and Reinforcement

NOTE 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. (8.2.1)
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. (8.2.2)
8.2.3 The nominal thickness of a single-ply membrane shall be as indicated in the datasheet.
Single-Ply Membrane Thicknessrange
mil
40455060728090
Per drawings — roof assembly schedule (deferred by default)
8.2.4 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.
8.2.5 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.
8.2.6 Single-ply membrane reinforcement shall be as indicated in the datasheet.
Single-Ply Membrane Reinforcementradio
○ Non-reinforced sheet
○ Internally scrim-reinforced sheet
○ Fabric-backed sheet
○ Fleece-backed sheet
○ Not applicable to a polymer-modified bitumen membrane
8.2.7 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.
8.2.8 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.

8.3 Polymer-Modified Bitumen Membrane Build-Up

NOTE 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. (8.3.1)
8.3.2 The number of polymer-modified bitumen plies shall be as indicated in the datasheet.
Polymer-Modified Bitumen Ply Countrange
plies
14
Per drawings — roof assembly schedule (deferred by default)
8.3.3 Each polymer-modified bitumen ply shall conform to the material specification identified for the membrane material selected in the datasheet.
8.3.4 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.
8.3.5 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.
8.3.6 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.

8.4 Membrane Surfacing

NOTE 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. (8.4.1)
8.4.2 Membrane surfacing shall be as indicated in the datasheet.
Membrane Surfacingradio
○ 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
8.4.3 Field-applied coatings shall be confirmed by the membrane manufacturer as compatible with the membrane and shall be applied at the published coverage rate.
8.4.4 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.
8.4.5 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.

8.5 Surface Color and Solar Reflectance

NOTE 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. (8.5.1)
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. (8.5.2)
8.5.3 The membrane surface color shall be as indicated in the datasheet.
Membrane Surface Colorradio
○ White
○ Light gray
○ Tan or beige
○ Black
○ Colored mineral granule surfacing
8.5.4 The solar reflectance requirement applying to the roof surface shall be as indicated in the datasheet.
Membrane Solar Reflectance Requirementradio
○ 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
8.5.5 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.
8.5.6 Where the specified membrane cannot meet an indicated reflectance requirement, the Contractor shall report the conflict before ordering material rather than after installation.

9 Thermoplastic Membrane Requirements

9.1 Scope of the Thermoplastic Article

NOTE Requirements in this article apply where TPO, PVC, or KEE is selected as the membrane material in the datasheet. (9.1.1)
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. (9.1.2)

9.2 Thermoplastic Seaming Method

9.2.1 All field seams, lap seams, and flashing seams in a thermoplastic membrane shall be hot-air welded.
9.2.2 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.
9.2.3 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.

9.3 Plasticizer and Bitumen Compatibility

NOTE 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. (9.3.1)
9.3.2 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.
9.3.3 Bituminous products shall not be placed in direct contact with a PVC membrane.
9.3.4 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.
9.3.5 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.

10 Thermoset EPDM Membrane Requirements

10.1 Scope of the EPDM Article

NOTE Requirements in this article apply where EPDM is selected as the membrane material in the datasheet. (10.1.1)
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. (10.1.2)
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. (10.1.3)

10.2 EPDM Seaming and Splicing

10.2.1 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.
10.2.2 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.
10.2.3 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.
10.2.4 Seam tape shall be applied continuously from one end of the splice to the other without lifting or repositioning.
10.2.5 Each completed splice shall be rolled with a steel roller across the full splice width, working from the center of the lap outward.
10.2.6 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.
10.2.7 Field-cut EPDM edges that remain exposed shall be treated with the manufacturer's lap edge sealant.

10.3 EPDM Dimensional Movement

NOTE 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. (10.3.1)
10.3.2 EPDM base flashings shall be continuously adhered to the vertical substrate for their full height.
10.3.3 EPDM base flashings shall lap onto the field membrane not less than 6 inches, spliced in accordance with this article.
10.3.4 EPDM base flashings shall be mechanically terminated at the top of the flashing in addition to being adhered.

11 Polymer-Modified Bitumen Membrane Requirements

11.1 Scope of the Bituminous Article

NOTE Requirements in this article apply where SBS or APP polymer-modified bitumen is selected as the membrane material in the datasheet. (11.1.1)
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. (11.1.2)

11.2 Bituminous Application Method Compatibility

11.2.1 Each polymer-modified bitumen ply shall be applied by a method the sheet manufacturer publishes for that sheet.
11.2.2 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.
11.2.3 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.
11.2.4 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.
11.2.5 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.
11.2.6 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.
11.2.7 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.

11.3 Bituminous Ply Bonding

11.3.1 Each ply shall be rolled or broomed into the bonding medium immediately after placement so that full contact is achieved before the medium sets.
11.3.2 Bitumen shall flow slightly and continuously ahead of the roll at every lap, confirming that the lap is fully bonded across its width.
11.3.3 Voids, fishmouths, and unbonded laps shall be cut, reset, and patched with the same sheet before the following ply is installed.
11.3.4 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.

12 Roof Insulation

12.1 Insulation Material

NOTE 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. (12.1.1)
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. (12.1.2)
12.1.3 Roof insulation material shall be as indicated in the datasheet.
Roof Insulation Materialcheckbox
☐ 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
12.1.4 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.
12.1.5 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.
12.1.6 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.
12.1.7 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.
12.1.8 Insulation shall not be installed in a greater quantity than can be covered by the membrane during the same work period.

12.2 Insulation Thermal Resistance

NOTE 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. (12.2.1)
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. (12.2.2)
12.2.3 The total thermal resistance of the roof insulation shall be as indicated in the datasheet.
Total Roof Insulation Thermal Resistancerange
h·ft²·°F/Btu
060
Per drawings — roof assembly schedule (deferred by default)
12.2.4 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.
12.2.5 Where polyisocyanurate insulation is used, the long-term thermal resistance value published under ASTM C1289 shall be used in that calculation.
12.2.6 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.

12.3 Insulation Layer Configuration

NOTE 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. (12.3.1)
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. (12.3.2)
12.3.3 The number of insulation layers shall be as indicated in the datasheet.
Number of Insulation Layersrange
layers
14
Per drawings — roof assembly schedule (deferred by default)
12.3.4 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.
12.3.5 Where insulation is installed in two or more layers, no joint shall align through the full thickness of the insulation.
12.3.6 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.
12.3.7 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.

12.4 Tapered Insulation

NOTE 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. (12.4.1)
12.4.2 Whether tapered insulation is used, and where, shall be as indicated in the datasheet.
Tapered Insulationradio
○ 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
12.4.3 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.
12.4.4 The tapered layout drawings shall be submitted and accepted before tapered material is fabricated.
12.4.5 Tapered panels shall be marked or keyed to the accepted layout drawings so that each panel is installed in its designed position.
12.4.6 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.
12.4.7 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.

13 Cover Board

13.1 Cover Board Selection

NOTE 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. (13.1.1)
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. (13.1.2)
13.1.3 The cover board shall be as indicated in the datasheet.
Cover Board Materialradio
○ 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
13.1.4 The cover board thickness shall be as indicated in the datasheet.
Cover Board Thicknessrange
in
0.250.3750.50.6250.751
Per drawings — roof assembly schedule (deferred by default)
13.1.5 The cover board specified shall appear in the assembly listing, classification, or test report relied on for uplift resistance and fire classification.
13.1.6 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.
13.1.7 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.

13.2 Cover Board Installation

13.2.1 Cover board joints shall be offset from the joints in the insulation layer below by not less than 6 inches in both directions.
13.2.2 Cover boards shall be installed with joints tight, without gaps that leave the membrane unsupported.
13.2.3 Cover boards shall be attached by the method and at the density required by the assembly relied on for uplift resistance.
13.2.4 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.

14 Vapor Retarder and Air Barrier Continuity

14.1 Vapor Retarder Determination

NOTE 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. (14.1.1)
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. (14.1.2)
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. (14.1.3)
14.1.4 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.
14.1.5 The vapor retarder class shall be as indicated in the datasheet.
Vapor Retarder Classradio
○ 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
14.1.6 Where the datasheet indicates no vapor retarder, the Contractor shall not install one on the Contractor's own initiative.

14.2 Vapor Retarder Materials and Installation

14.2.1 The vapor retarder material shall be as indicated in the datasheet.
Vapor Retarder Materialradio
○ 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
14.2.2 The vapor retarder shall be installed directly on the roof deck, below the insulation.
14.2.3 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.
14.2.4 Laps and end laps in a self-adhering vapor retarder shall be rolled to achieve full contact across the lap.
14.2.5 Penetrations through the vapor retarder shall be sealed with a compatible flashing sheet or tape before insulation is installed over them.
14.2.6 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.
14.2.7 Where the vapor retarder is fastened through the deck, the fastener pattern shall be that of the assembly relied on for uplift resistance.

14.3 Air Barrier Continuity at the Roof

NOTE 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. (14.3.1)
14.3.2 The roof air control layer shall be made continuous with the wall air barrier at every roof-to-wall and roof-to-parapet junction.
14.3.3 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.
14.3.4 Air barrier materials, testing, and performance criteria are governed by Air BarriersAir BarriersResolves to the current adopted revision.sync/air-barriers; this standard governs the roof-side termination of the transition.

15 Membrane and Insulation Attachment

15.1 Attachment Method Selection

NOTE 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. (15.1.1)
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. (15.1.2)
15.1.3 The membrane attachment method shall be as indicated in the datasheet.
Membrane Attachment Methodradio
○ 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
15.1.4 The attachment method selected shall be the method used in the assembly relied on for uplift resistance.
15.1.5 Attachment methods shall not be mixed within one roof zone unless the assembly relied on for uplift resistance covers the mixed condition.
15.1.6 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.

15.2 Mechanically Attached Membrane

NOTE 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. (15.2.1)
15.2.2 Fasteners and stress plates shall be installed within the seam lap at the spacing and row pattern required by the governing assembly.
15.2.3 Each stress plate shall seat flat on the membrane, fully bearing, without dishing the membrane or standing proud of it.
15.2.4 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.
15.2.5 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.
15.2.6 The seam lap shall extend beyond the edge of the stress plate by not less than the specified welded or spliced seam width.
15.2.7 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.

15.3 Induction-Welded Membrane

NOTE 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. (15.3.1)
15.3.2 Coated plates shall be installed at the pattern and density required by the governing assembly before the membrane is placed.
15.3.3 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.
15.3.4 Each bonded plate shall be weighted or magnetically clamped during cool-down for the period the equipment manufacturer publishes.
15.3.5 Bonds shall be verified by the method the membrane manufacturer publishes, and any plate that does not bond shall be re-welded or replaced.
15.3.6 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.

15.4 Adhered Membrane

NOTE 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. (15.4.1)
15.4.2 Bonding adhesive shall be applied at the coverage rate published for the adhesive and the substrate.
15.4.3 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.
15.4.4 Adhesive shall be allowed to reach the flash-off condition the manufacturer publishes before the membrane is rolled into it.
15.4.5 The Contractor shall verify the flash-off condition by hand test immediately before each section is rolled in.
15.4.6 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.
15.4.7 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.
15.4.8 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.
15.4.9 Self-adhered membranes shall be applied only within the substrate temperature range the manufacturer publishes and shall be rolled immediately after placement.

15.5 Ballasted Membrane

NOTE 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. (15.5.1)
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. (15.5.2)
15.5.3 Ballasted assemblies shall be designed in accordance with ANSI/SPRI RP-4 and IBC Section 1504.5.
15.5.4 The ballast material shall be as indicated in the datasheet.
Ballast Materialradio
○ 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
15.5.5 The ballast weight per unit area shall be as indicated in the datasheet.
Ballast Weightrange
psf
030
Per drawings — roof plan (deferred by default)
15.5.6 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.
15.5.7 Ballast gradation, weight, and the perimeter and corner enhancement shall match the ballasted system design relied on for uplift resistance.
15.5.8 The Structural Engineer of Record shall confirm in writing that the deck and framing carry the specified ballast dead load before ballast is placed.
15.5.9 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.
15.5.10 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.

15.6 Insulation and Cover Board Attachment

NOTE 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. (15.6.1)
15.6.2 The insulation and cover board attachment method shall be as indicated in the datasheet.
Insulation and Cover Board Attachment Methodradio
○ 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
15.6.3 Fasteners through insulation into the deck shall achieve the embedment the governing assembly requires for the deck type.
15.6.4 The Contractor shall calculate and verify fastener length against the total thickness of vapor retarder, insulation, cover board, and deck geometry before ordering fasteners.
15.6.5 Adhesive ribbons shall be applied at the bead width, bead spacing, and number of beads per board the governing assembly requires.
15.6.6 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.
15.6.7 Insulation shall not be loose-laid beneath a membrane that is mechanically attached or adhered, except where the governing assembly is a ballasted assembly.

15.7 Fasteners and Stress Plates

NOTE 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. (15.7.1)
15.7.2 Fastener corrosion resistance shall be as indicated in the datasheet.
Fastener Corrosion Resistanceradio
● Coated carbon steel meeting the corrosion resistance requirements of FM 4470
○ Austenitic stainless steel
○ Coated carbon steel with supplemental coating for severe marine exposure
15.7.3 Fasteners in steel deck shall be self-drilling, self-tapping screws listed for the deck gauge in the governing assembly.
15.7.4 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.
15.7.5 Fasteners in wood decks shall be ring-shank or threaded roofing fasteners listed for wood substrates.
15.7.6 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.
15.7.7 Fasteners and stress plates from different manufacturers shall not be combined in one attachment unless the governing assembly lists that combination.

16 Membrane Seaming

16.1 Membrane Layout and Lap Orientation

NOTE 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. (16.1.1)
16.1.2 Membrane sheets shall be laid out so that laps run parallel to the direction of slope wherever the roof geometry permits.
16.1.3 Where laps run across the slope, the upslope sheet shall lap over the downslope sheet.
16.1.4 End laps shall be staggered not less than 12 inches from end laps in adjacent sheet courses.
16.1.5 The membrane layout, including lap orientation and the location of every end lap, shall be shown on the shop drawings before installation begins.
16.1.6 Sheets shall be allowed to relax before seaming so that the sheet is not seamed under induced tension.

16.2 Hot-Air Welded Seams

NOTE 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. (16.2.1)
16.2.2 The minimum welded width of a machine-welded seam shall be as indicated in the datasheet.
Automatic Hot-Air Welded Seam Widthrange
in
13
Default: 1.5 in
16.2.3 The minimum welded width of a hand-welded seam shall be as indicated in the datasheet.
Hand-Welded Seam Widthrange
in
0.753
Default: 1 in
16.2.4 The welded width shall be measured on the completed seam after cooling, and shall be continuous for the full length of the seam.
16.2.5 Seam areas shall be cleaned of dirt, dust, and contamination immediately before welding.
16.2.6 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.
16.2.7 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.
16.2.8 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.
16.2.9 No lap intersection shall be left without a patch on a completed roof.

16.3 Tape-Spliced and Adhesive-Spliced Seams

16.3.1 The minimum lap width of a tape-spliced or adhesive-spliced seam shall be as indicated in the datasheet.
Tape-Spliced Seam Lap Widthrange
in
26
Default: 3 in
16.3.2 Splice tape and splice adhesive shall be products of the membrane manufacturer for the membrane being spliced.
16.3.3 Lap sealant shall be applied to the exposed edge of a tape-spliced seam where the membrane manufacturer requires it for the product.
16.3.4 Splices shall not be made when the splice surfaces are below the minimum temperature published for the tape or adhesive.

16.4 Polymer-Modified Bitumen Laps

16.4.1 The minimum side lap width of a polymer-modified bitumen sheet shall be as indicated in the datasheet.
Polymer-Modified Bitumen Side Lap Widthrange
in
26
Default: 3 in
16.4.2 The minimum end lap width of a polymer-modified bitumen sheet shall be as indicated in the datasheet.
Polymer-Modified Bitumen End Lap Widthrange
in
412
Default: 6 in
16.4.3 End laps in successive plies shall be staggered so that end laps do not align through the membrane thickness.
16.4.4 Laps shall be pressed or rolled while the bonding medium is fluid so that bitumen flows continuously at the lap edge.
16.4.5 Excess bitumen at a lap edge shall be struck smooth rather than left as a ridge that will collect debris.

17 Flashings and Terminations

17.1 Base Flashing

NOTE 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. (17.1.1)
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. (17.1.2)
17.1.3 The minimum base flashing height above the finished roof surface shall be as indicated in the datasheet.
Minimum Base Flashing Height Above Finished Roof Surfacerange
in
024
Default: 8 in
17.1.4 Base flashing shall be the same membrane material as the field membrane or a flashing sheet the membrane manufacturer publishes as compatible with it.
17.1.5 Base flashing shall be continuously bonded to the vertical substrate for its full height.
17.1.6 Base flashing shall be joined to the field membrane by the same seaming method used for the field seams of that membrane family.
17.1.7 Base flashing shall be mechanically terminated at its top edge.
17.1.8 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.
17.1.9 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.

17.2 Cants and Plane Transitions

NOTE 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. (17.2.1)
17.2.2 The treatment at horizontal-to-vertical transitions shall be as indicated in the datasheet.
Horizontal-to-Vertical Transition Treatmentradio
○ No cant strip
○ 45-degree cant strip at horizontal-to-vertical transitions
○ Tapered insulation edge strip at horizontal-to-vertical transitions
17.2.3 Where a cant strip is indicated, it shall be not less than 3 inches on each face and shall be continuous along the transition.
17.2.4 Cant strips and tapered edge strips shall be of a material the assembly relied on for fire classification permits.
17.2.5 Cant strips shall be secured so that they do not shift while the flashing is installed over them.
17.2.6 Where the datasheet indicates no cant strip, the flashing shall still be pressed fully into the corner and shall not bridge it.

17.3 Wall and Parapet Terminations

NOTE 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. (17.3.1)
17.3.2 Termination bars shall be installed on vertical surfaces.
17.3.3 Termination bars shall not be installed on a horizontal or upward-facing surface.
17.3.4 The termination bar material shall be as indicated in the datasheet.
Termination Bar Materialradio
● Extruded aluminum bar
○ Stainless steel bar
○ Galvanized steel bar
17.3.5 Termination bars shall be not less than 1/8 inch thick and shall be installed continuously along the top of the flashing.
17.3.6 The termination bar fastener spacing shall be as indicated in the datasheet.
Termination Bar Fastener Spacingrange
in o.c.
424
Default: 12 in o.c.
17.3.7 Termination bar fasteners shall be set not more than 6 inches from each end of each bar length and at each bar splice.
17.3.8 Sealant shall be applied along the top edge of the termination bar and into each fastener penetration.
17.3.9 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.
17.3.10 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.
17.3.11 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 Through Wall FlashingThrough-Wall Flashing and Masonry Moisture ControlResolves to the current adopted revision.sync/through-wall-flashing.

17.4 Penetration Flashing

NOTE 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. (17.4.1)
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. (17.4.2)
17.4.3 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.
17.4.4 The pipe penetration flashing method shall be as indicated in the datasheet.
Pipe Penetration Flashing Methodradio
○ 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
17.4.5 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.
17.4.6 Penetrations spaced closely together shall be individually flashed where the spacing permits a boot on each.
17.4.7 Where penetrations are too closely spaced to be individually flashed, they shall be curbed together and the curb shall be flashed as a curb.
17.4.8 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.
17.4.9 Every sealant-filled pitch pocket shall be identified on the record drawings and in the Owner's maintenance instructions.
17.4.10 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.

17.5 Equipment Curbs and Rooftop Supports

NOTE 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. (17.5.1)
17.5.2 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.
17.5.3 Curbs shall be rigid, continuously supported by the structure, and shall not deflect under the equipment they carry.
17.5.4 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.
17.5.5 Curb flashing shall be terminated mechanically at the top of the curb rather than relying on the equipment base for securement.
17.5.6 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.
17.5.7 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.
17.5.8 Equipment supports shall not be attached to the membrane by fasteners driven through the finished membrane.

17.6 Roof Drain and Scupper Interfaces

NOTE 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. (17.6.1)
17.6.2 The membrane shall be carried into the drain and clamped between the drain flange and the clamping ring.
17.6.3 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.
17.6.4 Clamping ring bolts shall be tightened evenly in sequence to the value the drain manufacturer publishes, without cutting or crushing the membrane.
17.6.5 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.
17.6.6 Insulation within the sump shall be tapered rather than stepped, so that the membrane is continuously supported into the drain.
17.6.7 Scupper openings shall be cut cleanly through the parapet and the opening shall be made smooth before flashing.
17.6.8 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.
17.6.9 Scupper liners shall be set in a sealant compatible with the membrane, and the membrane flashing shall be bonded over the liner flange.
17.6.10 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.
17.6.11 Drain bodies, strainers, and storm piping are governed by Roof DrainageRoof DrainageResolves to the current adopted revision.sync/roof-drainage; this standard governs the membrane termination at them.

17.7 Expansion and Area Divider Joints

NOTE 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. (17.7.1)
17.7.2 Structural expansion joints shall be carried through the roof assembly with a raised curbed expansion joint detail.
17.7.3 Expansion joint curbs shall be raised to not less than the base flashing height indicated in the datasheet on each side of the joint.
17.7.4 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.
17.7.5 The membrane shall not be carried continuously across a structural expansion joint.
17.7.6 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 as indicated on the roof plan.

17.8 Perimeter Edge Metal and Membrane Termination

17.8.1 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.
17.8.2 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.
17.8.3 Edge metal flanges that receive a membrane stripping ply shall be primed where the membrane manufacturer requires priming for the metal.
17.8.4 Edge metal joints shall be detailed to accommodate thermal movement, and the stripping over a joint shall accommodate that movement without tearing.
17.8.5 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.

18 Traffic Protection and Surfacing Installation

18.1 Walkway Protection

NOTE 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. (18.1.1)
18.1.2 Walkway protection shall be as indicated in the datasheet.
Walkway Protectionradio
○ 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
18.1.3 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.
18.1.4 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.
18.1.5 Walkway protection shall not be loose-laid on the membrane.
18.1.6 Walkway units shall be installed with a gap between adjacent units so that water drains between them rather than being impounded behind them.
18.1.7 Walkway protection shall not be installed over a seam, a lap intersection, or a flashing termination.

18.2 Ballast and Surfacing Placement

18.2.1 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.
18.2.2 Ballast at the perimeter and corner zones shall be placed at the increased weight, gradation, or paver substitution the ballasted system design requires.
18.2.3 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.
18.2.4 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.
18.2.5 Coating shall not be applied over standing water, dew, or a surface that has not been cleaned by the method the coating manufacturer publishes.

18.3 Protection of Completed Work

18.3.1 The Contractor shall protect completed membrane work from damage by subsequent roofing operations and by other trades.
18.3.2 The membrane shall not be used as a work surface or a staging area without protection board laid over it.
18.3.3 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.
18.3.4 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.
18.3.5 Solvents, fuels, oils, and cleaning chemicals shall not be stored or decanted on the membrane.
18.3.6 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.
18.3.7 Each repair shall be recorded on the record drawings with its location and the date of repair.

19 Testing and Inspection

19.1 Seam Verification

NOTE 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. (19.1.1)
19.1.2 Every field seam, lap seam, and flashing seam shall be probed with a rounded-tip seam probe after the seam has cooled.
19.1.3 Seam probing shall be performed by the installing operator for each seam on the day the seam is made.
19.1.4 The roofing foreman shall independently probe not less than 10 percent of the seams made each day.
19.1.5 A location where the probe enters the seam shall be marked, recorded, and repaired.
19.1.6 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.
19.1.7 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.
19.1.8 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.

19.2 Fastener Withdrawal Testing

NOTE 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. (19.2.1)
19.2.2 Whether fastener withdrawal testing is performed shall be as indicated in the datasheet.
Fastener Withdrawal Testingradio
○ Withdrawal testing per ANSI/SPRI FX-1 before the attachment pattern is finalized
○ No withdrawal testing — attachment values taken from published deck tables
19.2.3 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.
19.2.4 Test locations shall include each distinct deck type, gauge, and condition present in the work.
19.2.5 Test results shall be submitted with the proposed attachment pattern before the pattern is finalized.
19.2.6 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.
19.2.7 Test penetrations shall be sealed and, where they occur in an area already covered, patched with the membrane manufacturer's published repair detail.

19.3 Post-Installation Leak Testing

NOTE 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. (19.3.1)
19.3.2 Post-installation leak testing shall be as indicated in the datasheet.
Post-Installation Leak Testingcheckbox
☐ 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
19.3.3 Where flood testing is indicated, the test duration shall be as indicated in the datasheet.
Flood Test Durationrange
h
272
Default: 24 h
19.3.4 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.
19.3.5 The Structural Engineer of Record shall confirm in writing that the structure carries the flood test load before any area is flooded.
19.3.6 The area below a flooded area shall be observed for leakage during the test and at the end of the test period.
19.3.7 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.
19.3.8 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.
19.3.9 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.
19.3.10 The cost of retesting after a failed test shall be borne by the Contractor.

19.4 Verification Core Cuts

NOTE 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. (19.4.1)
19.4.2 Where verification core cuts are indicated, they shall be taken at the frequency and at the locations the Engineer of Record directs.
19.4.3 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.
19.4.4 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.
19.4.5 Each core cut shall be patched on the day it is taken using the membrane manufacturer's published repair detail.
19.4.6 Core cut locations shall be recorded on the record drawings.
19.4.7 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.
19.4.8 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.

19.5 Final Inspection and Punch List

19.5.1 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.
19.5.2 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.
19.5.3 The inspecting parties shall issue a written report identifying each item requiring correction.
19.5.4 The Contractor shall correct each identified item and shall notify the inspecting parties in writing when corrections are complete.
19.5.5 A follow-up inspection shall confirm that each item is resolved before warranty documents are executed.

20 Delivery, Storage, and Handling

20.1 Delivery and Product Protection

20.1.1 Membrane, insulation, and accessories shall be delivered in the manufacturer's original packaging with labels intact.
20.1.2 Materials shall be stored off the ground on pallets and shall be covered with a breathable, waterproof cover that is secured against wind.
20.1.3 Insulation and cover board shall be stored so that they remain dry, and any material that becomes wet shall be removed from the site.
20.1.4 Adhesives, primers, sealants, and coatings shall be stored within the temperature range the manufacturer publishes for storage.
20.1.5 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.
20.1.6 Materials shall be handled so that membrane rolls are not dropped on their ends and insulation boards are not damaged at their edges.

20.2 Rooftop Storage and Loading

NOTE 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. (20.2.1)
20.2.2 Materials shall be distributed on the roof so that no concentrated load exceeds the capacity of the deck and framing at that location.
20.2.3 The Contractor shall obtain the Structural Engineer of Record's written concurrence with the proposed rooftop staging loads before staging material on the roof.
20.2.4 Materials shall not be staged on completed membrane without protection board, and shall not be staged over an unsupported deck span.
20.2.5 Materials staged on the roof overnight shall be secured and covered against wind and precipitation.

21 Warranty

21.1 Contractor Workmanship Warranty

NOTE 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. (21.1.1)
21.1.2 The Contractor shall provide a written warranty against defects in workmanship and against leaks attributable to the installation.
21.1.3 The Contractor workmanship warranty term shall be as indicated in the datasheet.
Contractor Workmanship Warranty Termrange
years
110
Default: 2 years
21.1.4 The Contractor warranty shall run from the date of substantial completion.
21.1.5 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.
21.1.6 The Contractor warranty shall be in addition to, and shall not be reduced by, the manufacturer's warranty.
21.1.7 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.

21.2 Manufacturer System Warranty

NOTE 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. (21.2.1)
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. (21.2.2)
21.2.3 The membrane manufacturer's warranty type shall be as indicated in the datasheet.
Manufacturer Warranty Typeradio
○ 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
21.2.4 The membrane manufacturer's warranty term shall be as indicated in the datasheet.
Manufacturer Warranty Termrange
years
510121520253035
21.2.5 The peak gust wind speed covered by the manufacturer's warranty shall be as indicated in the datasheet.
Manufacturer Warranty Wind Speed Coveragerange
mph
55728090100120150
21.2.6 The scope of assembly components covered by the manufacturer's warranty shall be as indicated in the datasheet.
Manufacturer Warranty Coverage Scopecheckbox
☑ 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
21.2.7 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.
21.2.8 The Contractor shall report in writing, with the action submittal package, any project condition that would prevent issuance of the indicated warranty.
21.2.9 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.

21.3 Conditions Affecting Warranty Coverage

NOTE 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. (21.3.1)
21.3.2 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.
21.3.3 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.
21.3.4 Rooftop equipment shall be installed so that condensate, exhaust, and process discharge are routed to drainage rather than discharged onto the membrane surface.
21.3.5 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.
21.3.6 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.

22 Spare Materials and Owner Turnover

22.1 Spare Stock

NOTE 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. (22.1.1)
22.1.2 Spare stock shall be as indicated in the datasheet.
Spare Stock Furnished to the Ownercheckbox
☐ 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
22.1.3 Spare stock shall be from the same production lot as the installed materials where the manufacturer can supply it from that lot.
22.1.4 Spare stock shall be delivered in the manufacturer's original packaging, labeled with the product designation, lot number, and the roof areas it matches.
22.1.5 Spare stock shall be delivered to the location on the site the Owner designates and shall be receipted by the Owner.
22.1.6 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.

22.2 Roof Maintenance Documentation

NOTE 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. (22.2.1)
22.2.2 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.
22.2.3 The maintenance instructions shall identify every sealant-filled pitch pocket, every field repair, and every location requiring periodic sealant renewal.
22.2.4 The maintenance instructions shall state the procedure for authorizing and executing rooftop work after acceptance so that warranty coverage is preserved.
22.2.5 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.

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