SynC™

SynC · Editorial revision

Sheet Metal Flashing and Trim

Revision7
EditedAug 29, 2026
StatusCurrent
Contents

View changes in this revision   Revision history

Current revision. This is editorial revision 7, the current text of this standard. Read it on the standard's page.

SynC Standards Team — Specifier (Platform Standards) ✓ OfficialDiscloses employment SynC (SynC Platform Team)
Neutrality remake campaign: from-scratch field derivation per authoring cheatsheet; project parameters and derived dispositions

1 Scope

NOTE This standard covers the selection, fabrication, and installation of architectural sheet metal flashing and trim that closes the building envelope at roof edges, parapets, wall openings, material transitions, and drainage collection points. (1.1)
NOTE The work is interface work. Nearly every piece sits at the seam between two systems - roof and wall, wall and window, parapet and roof, or two structural bays that move independently - so each piece depends on the dimensional accuracy of adjacent construction and on being installed at the right point in the construction sequence. A coping fabricated exactly to the shop drawing still fails when it is set on out-of-level blocking, sized for the wrong parapet width, or installed after the membrane base flashing on the inside face has been cut short. (1.2)
NOTE The following are outside this standard and are covered elsewhere: (1.3)
  • Field membrane, membrane base flashings, and edge metal furnished by the membrane manufacturer as part of a warranted roof assembly.
  • Structural standing-seam metal roof panels, preformed wall panel systems, and rainscreen cladding, including gutters and trim integral to those systems.
  • Wood nailers, blocking, and curbs that receive sheet metal anchorage.
  • Lightning protection components, HVAC ductwork, and below-grade waterproofing terminations.
1.4 The Contractor shall verify substrate dimensions, elevations, and conditions in the field before releasing any piece for fabrication.
1.5 The Contractor shall coordinate the sheet metal sequence with the roofing, masonry, framing, glazing, and cladding trades before fabrication begins.
1.6 Where a piece within this scope is furnished under another scope of work, the Contractor shall identify that piece in the shop drawings and shall coordinate its interface details with the furnishing trade.

2 Referenced Standards

2.1 Materials, 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
SMACNA Architectural Sheet Metal Manual Architectural Sheet Metal Manual (forming, joint, cleat, hem, and expansion joint details)
ANSI/SPRI/FM 4435/ES-1 Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems
FM 4435 Approval Standard for Edge Systems Used with Low Slope Roofing Systems
ASCE 7 Minimum Design Loads and Associated Criteria for Buildings and Other Structures
IBC International Building Code (Chapter 15, Roof Assemblies and Rooftop Structures)
ASTM A653/A653M Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process
ASTM A792/A792M Steel Sheet, 55% Aluminum-Zinc Alloy-Coated by the Hot-Dip Process
ASTM A924/A924M General Requirements for Steel Sheet, Metallic-Coated by the Hot-Dip Process
ASTM A755/A755M Steel Sheet, Metallic Coated by the Hot-Dip Process and Prepainted by the Coil-Coating Process for Exterior Exposed Building Products
ASTM A240/A240M Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip
ASTM A480/A480M General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and Strip
ASTM A153/A153M Zinc Coating (Hot-Dip) on Iron and Steel Hardware
ASTM B209/B209M Aluminum and Aluminum-Alloy Sheet and Plate
ASTM B370 Copper Sheet and Strip for Building Construction
ASTM B69 Rolled Zinc
ASTM B32 Solder Metal
ASTM C920 Elastomeric Joint Sealants
ASTM C1193 Use of Joint Sealants
ASTM C1087 Determining Compatibility of Liquid-Applied Sealants with Accessories Used in Structural Glazing Systems
ASTM D1970/D1970M Self-Adhering Polymer Modified Bituminous Sheet Materials Used as Steep Roofing Underlayment for Ice Dam Protection
ASTM D4214 Evaluating the Degree of Chalking of Exterior Building Paint Films
ASTM D2244 Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates
ASTM E2140 Water Penetration of Metal Roof Panel Systems by Static Water Pressure Head
AAMA 2603 Pigmented Organic Coatings on Aluminum Extrusions and Panels
AAMA 2604 High Performance Organic Coatings on Aluminum Extrusions and Panels
AAMA 2605 Superior Performing Organic Coatings on Aluminum Extrusions and Panels
AAMA 611 Anodized Architectural Aluminum
AAMA 501.2 Field Check of Metal Curtain Walls for Water Leakage
NRCA Roofing Manual Membrane Roof Systems (architectural metal flashing details and edge metal guidance)
CDA Copper in Architecture Handbook Copper Development Association handbook for architectural copper design and detailing
SSINA Designer Handbook Specialty Steel Industry of North America handbook for stainless steel fabrication and finishing

3 Submittals

3.1 Action Submittals

3.1.1 The Contractor shall submit the following for the Engineer of Record's review and approval before ordering material or releasing any piece for fabrication:
  • Product data for each sheet metal type, identifying the governing ASTM specification, base metal thickness, coating designation, alloy and temper, and finish system.
  • Finish system data for each coil-applied or anodized finish, including the AAMA specification conformance, color, gloss, and the finish manufacturer's warranty form.
  • ANSI/SPRI ES-1 test report and product label documentation for each roof-edge profile, showing the tested resistance against the design pressure computed for the building's perimeter and corner zones.
  • Shop drawings showing each fabricated piece in plan, section, and elevation, with dimensions, girths, metal thickness, hem and return geometry, joint type and location, cleat type and fastener spacing, expansion joint locations, and corner and termination conditions.
  • Layout drawings locating every expansion joint, cleat run, downspout, scupper, conductor head, and field joint on the building elevations.
  • Samples of each metal and finish on the actual specified substrate, sized large enough to judge color, gloss, and texture in daylight.
  • Fabricator and installer qualification statements with project references for the metal types and joining methods in this scope.
  • Sealant compatibility and adhesion test data for each sealant in contact with a coil-applied, anodized, or bare metal surface, including any primer the sealant manufacturer requires.
  • Fabrication girth and yield plan for copper, zinc, and stainless steel scopes, confirming that pan widths and seam locations match the details being followed.
Action Submittals Requiredcheckbox
☑ Product data for each sheet metal type
☑ Finish system data and finish manufacturer warranty form
☑ ANSI/SPRI ES-1 test report and product label documentation for each roof-edge profile
☑ Shop drawings of each fabricated piece
☑ Layout drawings locating expansion joints, cleats, and drainage components
☑ Samples of each metal and finish on the specified substrate
☑ Fabricator and installer qualification statements
☐ Sealant compatibility and adhesion test data
☐ Fabrication girth and yield plan for copper, zinc, and stainless steel
3.1.2 A roof-edge submittal that omits the ES-1 test documentation for the profile, cleat, fastener pattern, and substrate actually proposed shall be returned as incomplete.
3.1.3 The Contractor shall not release roof-edge metal for fabrication before the ES-1 documentation is accepted.

3.2 Informational Submittals

3.2.1 The Contractor shall submit the following for record before installation begins:
  • Pre-installation conference minutes, including the agreed sequence with the roofing, masonry, and cladding trades.
  • Written substrate acceptance or a written notice of deficient substrate conditions for each area before sheet metal is set in that area.
  • Certification of the solder alloy and flux proposed for each soldered metal.
  • The finish manufacturer's written statement that the project exposure falls within the finish warranty's covered conditions.
Informational Submittals Requiredcheckbox
☑ Pre-installation conference minutes
☑ Written substrate acceptance or notice of deficient conditions
☐ Solder alloy and flux certification
☑ Finish manufacturer statement on project exposure

3.3 Closeout Submittals

3.3.1 The Contractor shall submit the following at substantial completion, before the sheet metal work is accepted:
  • Executed finish manufacturer warranty covering film integrity, chalk, and color change.
  • Executed workmanship warranty from the Contractor covering fabrication, joinery, and installation.
  • Record shop drawings marked to show as-installed expansion joint locations, every field-formed or field-cut piece, and every field repair.
  • Maintenance instructions for cleaning, periodic inspection, and sealant joint renewal, prepared by the fabricator or the finish manufacturer.
  • Touch-up material in the specified colors, in sealed factory containers, labeled with the finish system and color designation.
Closeout Submittals Requiredcheckbox
☑ Executed finish manufacturer warranty
☑ Executed Contractor workmanship warranty
☑ Record shop drawings marked with as-installed conditions
☑ Maintenance instructions for cleaning, inspection, and sealant renewal
☑ Touch-up material in sealed labeled containers

4 Quality Assurance

4.1 Fabricator and Installer Qualifications

Minimum Fabricator Experience in the Specified Metals and Joining Methodsrange
years
2351015
Minimum Installer Experience on Comparable Architectural Sheet Metal Workrange
years
2351015
4.1.1 The fabricator shall have the experience indicated in the datasheet in the metal types, thicknesses, finishes, and joining methods specified for this project.
4.1.2 The fabricator shall have brake and roll-forming capacity for the longest and heaviest piece shown on the shop drawings.
4.1.3 Soldering of copper, lead-coated copper, and stainless steel shall be performed by operators who have soldered the same metal at the same thickness on previous work.
4.1.4 Welding of stainless steel and aluminum shall be performed by welders qualified for the process, position, and thickness shown on the shop drawings.
4.1.5 The installer shall coordinate directly with the roofing Contractor at every interface between this scope and the membrane assembly.
4.1.6 Where the roof carries a membrane manufacturer's no-dollar-limit warranty, edge metal integrated into the warranted assembly shall be installed by an installer the membrane manufacturer accepts for that assembly, or under a written coordination arrangement the membrane manufacturer confirms preserves the warranty.

4.2 Pre-Installation Conference

4.2.1 A pre-installation conference shall be held before any sheet metal is set.
4.2.2 Attendance shall include the sheet metal installer, the roofing Contractor, the masonry or cladding contractor, the General Contractor, the Engineer of Record, and the Owner's representative.
4.2.3 The conference shall establish the installation sequence with the roofing and wall trades, confirm expansion joint locations, review the ES-1 fastener pattern, confirm sealant joint design and dissimilar-metal separation, and set the field cutting and touch-up policy.
4.2.4 The General Contractor shall distribute conference minutes to all attendees within five business days of the conference.

4.3 Mock-Up and First-of-Type Review

Mock-Up Required Before Production Fabricationradio
○ Freestanding mock-up erected at a location selected by the Engineer of Record
○ In-place first-of-type installation reviewed before production work continues
○ Not required
Conditions to Be Represented in the Mock-Upcheckbox
☑ Outside corner
☐ Inside corner
☑ Expansion joint
☑ Running field joint
☑ End termination against an adjacent material
☑ Drip edge and hem
☐ Exposed fastener condition
☐ Cleat and anchorage concealed behind the finished face
4.3.1 Where a mock-up is indicated in the datasheet, production fabrication shall not proceed until the Engineer of Record has accepted the mock-up in writing.
4.3.2 The mock-up shall represent each condition selected in the datasheet, using the specified metal, thickness, finish, joint type, and anchorage.
4.3.3 An accepted in-place mock-up may remain in the finished work where it is undamaged and conforms to the accepted submittals.
4.3.4 The Engineer of Record shall be the initial arbiter of whether an accepted mock-up establishes the standard of workmanship for a disputed area of finished work.

5 Environmental and Service Conditions

NOTE Metal selection, finish selection, and fastener selection all depend on the chemistry the assembly will sit in for the life of the building, and the corrosivity of a site is not always obvious from its address - a roof downwind of a cooling tower, a fume stack, or a de-icing operation can be far more aggressive than its geographic setting suggests. (5.1)
Atmospheric Corrosivity of the Siteradio
○ Rural or suburban inland
○ Urban
○ Industrial with airborne acid or particulate fallout
○ Marine within one mile of salt water
○ Marine between one and five miles of salt water
○ Inland site with routine de-icing salt exposure
○ Agricultural with ammonia exposure
○ Indoor conditioned space
○ Indoor unconditioned or permanently concealed space
Design Surface Temperature Range Used for Thermal Movementrange
°F
6080100120140160180200220240
5.1.1 The design surface temperature range in the datasheet shall govern the calculation of thermal movement, joint spacing, and slip-joint travel for every running piece in this scope.
5.1.2 The Contractor shall report to the Engineer of Record any known local source of corrosive discharge within one hundred feet of the sheet metal work that the datasheet exposure category does not already reflect.
NOTE Surface temperature range is wider than air temperature range, because a dark exposed metal surface in full sun reaches well above ambient and a clear-sky surface at night radiates below it. Basing joint spacing on the annual air temperature swing alone understates the movement the joint actually sees. (5.1.3)

6 Sheet Metal Selection by Assembly

6.1 Selection Basis

NOTE Each assembly family in this scope makes its own metal selection, because the governing considerations differ. Roof-edge metal is a wind-securement component; counterflashing is a removable protective cover; gutters carry standing water and ice; closure trim is often the most visible metal on the building and the least structurally loaded. A single project-wide metal is a legitimate choice, and so is a different metal for each family. (6.1.1)
NOTE Galvanic compatibility constrains the set of selections that can coexist on one building. Copper in contact with aluminum, zinc, or zinc-coated steel, copper-bearing runoff washing onto those metals from above, and carbon steel fasteners in stainless or aluminum sheet all drive corrosion that continues for the life of the assembly. (6.1.2)
6.1.3 The metal type for each assembly family shall be as indicated in the datasheet.
Roof-Edge and Coping Sheet Metalradio
○ Prefinished coil-coated zinc-coated steel
○ Prefinished coil-coated aluminum-zinc alloy-coated steel
○ Mill-finish zinc-coated steel
○ Mill-finish aluminum-zinc alloy-coated steel
○ Prefinished coil-coated aluminum
○ Anodized aluminum
○ Mill-finish aluminum
○ Stainless steel
○ Terne-coated stainless steel
○ Copper
○ Lead-coated copper
○ Architectural zinc
Counterflashing and Wall Flashing Sheet Metalradio
○ Prefinished coil-coated zinc-coated steel
○ Prefinished coil-coated aluminum-zinc alloy-coated steel
○ Mill-finish zinc-coated steel
○ Mill-finish aluminum-zinc alloy-coated steel
○ Prefinished coil-coated aluminum
○ Anodized aluminum
○ Mill-finish aluminum
○ Stainless steel
○ Terne-coated stainless steel
○ Copper
○ Lead-coated copper
○ Architectural zinc
Gutter, Downspout, and Scupper Sheet Metalradio
○ Prefinished coil-coated zinc-coated steel
○ Prefinished coil-coated aluminum-zinc alloy-coated steel
○ Mill-finish zinc-coated steel
○ Mill-finish aluminum-zinc alloy-coated steel
○ Prefinished coil-coated aluminum
○ Anodized aluminum
○ Mill-finish aluminum
○ Stainless steel
○ Terne-coated stainless steel
○ Copper
○ Lead-coated copper
○ Architectural zinc
Closure, Reveal, and Miscellaneous Trim Sheet Metalradio
○ Prefinished coil-coated zinc-coated steel
○ Prefinished coil-coated aluminum-zinc alloy-coated steel
○ Mill-finish zinc-coated steel
○ Mill-finish aluminum-zinc alloy-coated steel
○ Prefinished coil-coated aluminum
○ Anodized aluminum
○ Mill-finish aluminum
○ Stainless steel
○ Terne-coated stainless steel
○ Copper
○ Lead-coated copper
○ Architectural zinc
6.1.4 The Contractor shall not substitute a metal type, coating class, or finish system for the selections in the datasheet without written approval from the Engineer of Record.
6.1.5 A request to substitute shall state the galvanic relationship between the proposed metal and every metal it will contact or drain onto.

6.2 Sheet Thickness Basis

6.2.1 Sheet thickness for each piece shall be not less than the SMACNA Architectural Sheet Metal Manual value for that piece type, girth, span between supports, and metal, and shall be not less than the thickness indicated in the datasheet for the metal used.
6.2.2 The Contractor shall increase thickness above the datasheet value where the shop drawing girth or span exceeds the range the datasheet thickness covers, at no change in Contract Sum where the girth is shown in the Contract Documents.
NOTE Thickness is the cheapest stiffness available in formed sheet metal. Thin sheet on a long span shows oil-canning across the flat face, distorts at seams under thermal load, and pulls at cleats in wind. Heavier sheet resists all three but demands a larger inside bend radius and greater brake capacity, and it costs more per square foot. (6.2.3)

7 Zinc-Coated and Aluminum-Zinc Alloy-Coated Steel Sheet

7.1 Steel Substrate and Metallic Coating

Zinc Coating Designation for Zinc-Coated Steel Sheetradio
○ G30
○ G60
● G90
○ G115
○ G165
○ G185
Coating Designation for Aluminum-Zinc Alloy-Coated Steel Sheetradio
● AZ50
○ AZ55
○ AZ60
Steel Sheet Minimum Thicknessselect
28 ga
26 ga
24 ga
22 ga
20 ga
18 ga
16 ga
7.1.1 Zinc-coated steel sheet shall conform to ASTM A653/A653M with the coating designation indicated in the datasheet, and the general requirements of ASTM A924/A924M shall apply.
7.1.2 Aluminum-zinc alloy-coated steel sheet shall conform to ASTM A792/A792M with the coating designation indicated in the datasheet.
7.1.3 Where flashing or trim is exposed to exterior weather, the zinc coating designation shall be not less than G90.
7.1.4 Where flashing or trim is exposed to exterior weather, the aluminum-zinc alloy coating designation shall be not less than AZ50.
7.1.5 The base steel shall be commercial steel or forming steel of a grade suited to the forming severity shown on the shop drawings.
7.1.6 Prepainted steel sheet shall conform to ASTM A755/A755M for the metallic coating, primer, and topcoat system.
NOTE A coating designation states the mass of metallic coating per unit area over both surfaces, so a higher number is more coating and more time before the base steel is exposed. Cut edges are protected sacrificially by the adjacent coating rather than by coating over the edge, which is why a cut edge standing in water lasts far less time than the same edge shedding water. (7.1.7)
7.1.8 Cut edges of zinc-coated and aluminum-zinc alloy-coated steel shall not be left in locations where water stands.
7.1.9 Where a bare cut edge is unavoidable in an exposed location, it shall receive a zinc-rich touch-up coating or the finish manufacturer's approved edge treatment.
NOTE The aluminum-rich coating on aluminum-zinc alloy-coated steel outlasts an equivalent zinc coating in most atmospheric exposures, and loses that advantage in continuously alkaline contact, where high-pH water dissolves the aluminum-rich phase. Mortar runoff, fresh concrete, and animal-confinement environments are the common alkaline conditions on a building. (7.1.10)
7.1.11 Aluminum-zinc alloy-coated steel shall be separated from fresh mortar, fresh concrete, and continuously wet alkaline surfaces by a barrier that prevents alkaline runoff from reaching the metal.

8 Aluminum Sheet

8.1 Aluminum Alloy, Temper, and Thickness

Aluminum Alloy and Temperradio
○ 1100-H14
○ 3003-H14
○ 3004-H16
○ 3105-H14
○ 5005-H14
○ 5005-H34
○ 5052-H32
Aluminum Sheet Minimum Thicknessrange
in
0.0190.0240.0320.040.050.0630.080.125
8.1.1 Aluminum sheet shall conform to ASTM B209/B209M in the alloy and temper indicated in the datasheet.
8.1.2 Where an anodized finish is specified, the alloy and temper shall be one the anodizer confirms in writing will produce uniform color across the full order.
8.1.3 Aluminum shall not be placed in direct contact with fresh mortar, fresh concrete, or lumber treated with a copper-bearing preservative unless a separation material conforming to the galvanic separation requirements of this standard is installed between them.
NOTE Aluminum is light enough to handle in long lengths, holds a coil-applied finish well, and forms readily in the thicknesses used for flashing. Its coefficient of thermal expansion is roughly twice that of steel, so an aluminum run of a given length needs proportionally more movement capacity than a steel run of the same length. (8.1.4)
8.1.5 Aluminum trim shall not be used as a structural support for another element unless the shop drawings show the support condition and it has been reviewed by the Engineer of Record.

9 Stainless Steel Sheet

9.1 Stainless Grade and Surface Finish

Stainless Steel Graderadio
○ Type 304
○ Type 304L
○ Type 316
○ Type 316L
○ Type 430
○ Type 2205 duplex
Stainless Steel Surface Finishradio
● No. 2B mill finish
○ No. 2D mill finish
○ No. 3 coarse polished
○ No. 4 brushed satin
○ No. 6 fine satin
○ No. 8 mirror polished
○ Bead blasted
○ Rigidized or embossed pattern
Stainless Steel Sheet Minimum Thicknessrange
in
0.0120.0150.01870.0250.03120.03750.050.075
9.1.1 Stainless steel sheet shall conform to ASTM A240/A240M, with surface finish designations and finish tolerances per ASTM A480/A480M.
9.1.2 Where the sheet metal is exposed to chloride from salt water, salt spray, or de-icing operations, the grade shall be one containing molybdenum.
9.1.3 Where the finished face will be viewed at close range in reflected light, the finish shall be selected and sampled with the Engineer of Record before fabrication, and the direction of the polishing grain shall be shown on the shop drawings.
9.1.4 Protective film on polished stainless steel shall remain in place through fabrication and installation and shall be removed at substantial completion.
NOTE Stainless steel outlasts every other common architectural sheet metal in chloride exposure, and it is also the hardest of them to work: it work-hardens under the brake, needs a larger inside bend radius before it cracks, resists soldering in heavier thicknesses, and costs the most per pound. A polished finish also shows every forming mark, so the finish decision and the forming decision are made together. (9.1.5)

10 Copper Sheet

10.1 Copper Weight, Temper, and Surface Condition

Copper Sheet Weightrange
oz/ft²
121620243248
Copper Temperradio
○ O60 soft temper
● H00 cold-rolled temper
○ H01 cold-rolled high-yield temper
Copper Surface Condition at Installationradio
● Mill finish, left to weather naturally
○ Factory pre-patinated
○ Factory pre-oxidized to a brown tone
○ Lead-coated
○ Tin-zinc coated
10.1.1 Copper sheet shall conform to ASTM B370 in the weight, temper, and surface condition indicated in the datasheet.
10.1.2 Copper weight in the datasheet is nominal weight per square foot; the corresponding nominal thickness is as follows:
Nominal weight Nominal thickness
12 oz/ft² 0.0162 in
16 oz/ft² 0.0216 in
20 oz/ft² 0.0270 in
24 oz/ft² 0.0323 in
32 oz/ft² 0.0431 in
48 oz/ft² 0.0646 in
10.1.3 Copper shall not be installed in direct contact with aluminum, zinc, zinc-coated steel, or uncoated carbon steel.
10.1.4 Where copper drains onto a less noble metal, the metal below shall be protected by a continuous non-reactive separation layer, or the drainage path shall be revised so that copper runoff does not reach it.
10.1.5 Where copper drains onto a porous surface that will remain visible, the copper drip line shall be detailed to carry water clear of that surface, or the surface shall be protected by an intervening element.
10.1.6 The Contractor shall confirm in writing that the Owner has been informed of the weathering sequence before mill-finish copper is released for fabrication.
NOTE Mill-finish copper passes through bright metal, then a range of browns, then a green or blue-green carbonate patina, over a period that runs from several years to several decades depending on exposure and rainfall. The patina is itself the protective layer, and the transition is uneven where rainfall reaches the surface unevenly. Factory pre-patination shortens the wait and narrows the variation; it does not eliminate later change. (10.1.7)
10.1.8 Lead-coated copper shall be used only where the project's environmental and worker-protection requirements for lead-bearing materials have been reviewed and satisfied, and those requirements shall be identified in the submittal.

11 Architectural Zinc Sheet

11.1 Zinc Alloy, Thickness, and Underside Ventilation

Architectural Zinc Sheet Thicknessrange
mm
0.60.70.811.21.5
Architectural Zinc Surface Condition at Installationradio
○ Mill finish, left to weather naturally
○ Factory pre-weathered to a light gray tone
○ Factory pre-weathered to a dark gray tone
○ Factory coated in a pigmented finish
Underside Ventilation Provision Beneath Architectural Zincradio
○ Ventilated cavity formed by a drainage and ventilation mat
○ Ventilated cavity formed by counter-battens
○ Structured separation layer over a solid deck
○ Not applicable because the zinc face is fully exposed on both sides
11.1.1 Architectural zinc sheet shall conform to ASTM B69 in the thickness indicated in the datasheet.
11.1.2 The underside of architectural zinc shall be ventilated by the provision indicated in the datasheet, installed to the zinc manufacturer's published details.
11.1.3 Architectural zinc shall not be installed over an underlayment or substrate that holds moisture against its underside.
11.1.4 Architectural zinc shall not be placed in contact with copper, copper-bearing runoff, oak or chestnut, or continuously wet alkaline surfaces.
NOTE Zinc protects itself with a carbonate patina that forms in atmospheric exposure and reforms over scratches. That patina needs alternating wetting and drying to develop. Where the underside stays wet, the patina does not form and a rapidly progressing white corrosion attacks the metal instead, which is why the ventilation provision matters more for zinc than for any other sheet metal in this scope. (11.1.5)
NOTE Rolled zinc expands anisotropically. Along the rolling direction its coefficient of thermal expansion is roughly 19 × 10⁻⁶ in/in/°F, and across the rolling direction roughly 12 × 10⁻⁶, so the rolling direction of each piece is part of the movement calculation and not an incidental fabrication detail. (11.1.6)
11.1.7 The rolling direction of each zinc piece shall be shown on the shop drawings.

12 Coil-Applied and Anodized Finishes

12.1 Coil-Applied Organic Coatings

Coil-Applied Coating Performance Classradio
○ AAMA 2603
○ AAMA 2604
○ AAMA 2605
Coating Color and Gloss Selectiontext
Enter value...
Per drawings — finish schedule (deferred by default)
Coating System Applied to the Concealed Faceradio
○ Wash coat primer
○ Full backer coat
○ Same topcoat system as the exposed face
12.1.1 Coil-applied organic coatings shall conform to the AAMA performance class indicated in the datasheet, applied over the pretreatment and primer the coating manufacturer specifies for the substrate.
NOTE The three AAMA classes are distinguished by the length of South Florida exposure the coating must survive within stated limits on color change, chalk, gloss retention, and film integrity: one year for AAMA 2603, five years for AAMA 2604, and ten years for AAMA 2605. Longer qualifying exposure buys longer service appearance and costs more per square foot. (12.1.2)
12.1.3 Where the finished face is exposed to direct sunlight and is visible from a public way or an occupied space, the coating class shall be not less than AAMA 2604.
12.1.4 Where the coating is selected in a saturated or organic pigment color, the Contractor shall obtain the coating manufacturer's specific color data, because color change limits are more difficult to hold in those pigment families.
12.1.5 The Contractor shall confirm coil order quantity, color, and lead time at the time of submittal, and shall report to the General Contractor any lead time that affects the construction schedule.

12.2 Anodized Aluminum Finishes

Anodized Coating Classradio
● AAMA 611 Class I
○ AAMA 611 Class II
Anodized Finish Colorradio
○ Clear
○ Champagne
○ Light bronze
○ Medium bronze
○ Dark bronze
○ Black
12.2.1 Anodized aluminum shall conform to AAMA 611 at the coating class indicated in the datasheet.
12.2.2 Where anodized aluminum is exposed to exterior weather, the coating class shall be AAMA 611 Class I.
12.2.3 All anodized aluminum visible on a single building elevation shall be produced from one lot, and the Contractor shall confirm lot continuity before the order is released.
12.2.4 The Contractor shall obtain the Engineer of Record's written acceptance of the color variation range before anodized material is ordered.
NOTE Anodizing converts the aluminum surface rather than covering it, so its color comes from the metal, the alloy, and the bath, and it varies measurably between coils and between lots. That variation is a property of the process, not a defect, and it is managed by lot control rather than by rejection after delivery. (12.2.5)

12.3 Mill and Natural Surfaces

12.3.1 Where a mill or naturally weathering surface is specified, the Contractor shall confirm in writing that the Owner has been informed of the appearance sequence and has accepted the initial unweathered appearance.
NOTE A mill or naturally weathering surface cannot later be converted to the appearance of a factory-applied finish in place. The substitution decision is made before fabrication or not at all. (12.3.2)

12.4 Field Touch-Up of Applied Finishes

Largest Damaged Area Eligible for Field Touch-Up on an Exposed Surfacerange
in
0.250.512
12.4.1 Touch-up material shall be the coating manufacturer's product for the specified coating system and color.
12.4.2 Touch-up on an exposed surface shall be limited to damage no larger than the dimension indicated in the datasheet in any direction.
12.4.3 A piece with exposed-face damage larger than the datasheet dimension shall be replaced rather than touched up.
12.4.4 Cut edges concealed within a hem, fastener heads concealed beneath sealant, and other surfaces not in direct sunlight may receive touch-up at any size.
NOTE A field-applied touch-up weathers on a different curve than the factory-cured coating around it, so an eye-level patch that matches on the day it is applied separates visibly within a few seasons. That is why the eligible size is small and tied to visibility rather than to the cost of replacement. (12.4.5)

13 Fasteners, Cleats, and Anchorage

13.1 Attachment Method

Attachment Method for Exposed Sheet Metal Facesradio
○ Concealed attachment using continuous cleats, hook strips, or clips
○ Exposed fasteners with bonded sealing washers
○ Concealed attachment at the running face with exposed fasteners at terminations
NOTE Where the sheet metal face is visible in the finished work, concealed attachment removes the exposed-fastener field entirely, which removes the sealing washers that age, the fastener heads that hold water and stain, and the visual rhythm of a fastener line across the face. Exposed fasteners cost less to install and are faster to remove for service. (13.1.1)
13.1.2 Attachment shall be as indicated in the datasheet.
13.1.3 Exposed fasteners shall be color-matched to the adjacent finish or concealed beneath a trim closure.
13.1.4 Fasteners shall not penetrate the water-bearing surface of a gutter, pan flashing, or scupper.

13.2 Fastener Material and Corrosion Compatibility

Exposed Fastener Materialradio
● Type 304 stainless steel with bonded sealing washer
○ Type 316 stainless steel with bonded sealing washer
○ Aluminum with bonded sealing washer
○ Silicon bronze
○ Copper or copper alloy
○ Hot-dip galvanized steel with bonded sealing washer
Concealed Fastener Materialradio
● Type 304 stainless steel
○ Type 316 stainless steel
○ Aluminum
○ Silicon bronze
○ Copper or copper alloy
○ Hot-dip galvanized steel
13.2.1 Fasteners shall be of the same metal as the sheet they secure, or of a metal not less noble than that sheet.
13.2.2 Hot-dip galvanized steel fasteners shall conform to ASTM A153/A153M and shall not be used in copper, stainless steel, or terne-coated stainless steel sheet.
13.2.3 Copper sheet shall be fastened with copper, copper alloy, or stainless steel fasteners.
13.2.4 Architectural zinc shall be fastened with stainless steel fasteners.
13.2.5 Fasteners into wood substrate shall achieve the embedment the ES-1 listing or the shop drawing detail requires, and shall not be substituted with a shorter fastener to suit a field condition.
NOTE A fastener less noble than the sheet becomes the anode for the whole assembly. The fastener is a small area against a large cathode, so it corrodes fast, and the sheet then loses its anchorage before it shows any distress of its own. Reversing the relationship reverses the outcome: a noble fastener in a less noble sheet loses only the small ring of sheet in contact with it. (13.2.6)

13.3 Cleats and Hook Strips

Cleat Typeradio
● Continuous cleat running the full length of the piece
○ Intermittent clip cleat
Intermittent Cleat Maximum Spacingrange
in o.c.
46812161824
Intermittent Cleat Minimum Widthrange
in
11.52346
NOTE A cleat is a strip of metal fastened to the substrate that engages a hemmed return on the sheet metal piece, holding the piece against uplift without any fastener through the visible face. (13.3.1)
13.3.2 Cleats shall be of the same metal as the sheet they engage, or of a compatible metal not less noble than that sheet.
13.3.3 Cleat thickness shall be not less than the thickness of the sheet it engages.
13.3.4 Where the sheet is at the lower end of the thickness range for its girth and span, the cleat shall be one thickness step heavier than the sheet.
13.3.5 Continuous cleats shall be installed in lengths matching the piece they engage, butted rather than lapped at cleat-to-cleat joints, and positioned so that a cleat joint does not coincide with a sheet metal joint.
13.3.6 Intermittent cleats shall be not narrower than the datasheet width and shall be spaced no farther apart than the datasheet spacing.
13.3.7 Intermittent cleats shall be bedded in non-curing tape sealant between the cleat and the substrate.
NOTE A continuous cleat engages the hem along its whole length, so uplift is carried uniformly by the fold. An intermittent cleat carries the same total load through discrete points, which concentrates the engagement and can telegraph as local distortion along a hem in a long exposed run. (13.3.8)

14 Sealants, Tapes, and Underlayment

14.1 Elastomeric Sealants at Weather-Exposed Joints

Elastomeric Sealant Chemistry at Weather-Exposed Sheet Metal Jointsradio
○ Silicone
○ Polyurethane
○ Silyl-terminated polyether hybrid
○ Polysulfide
Sealant Movement Class to ASTM C920radio
○ Class 12-1/2
○ Class 25
● Class 50
○ Class 100/50
14.1.1 Elastomeric sealant shall conform to ASTM C920, Type S or Type M, Grade NS, at the movement class indicated in the datasheet, in Use classes covering the substrates it contacts.
14.1.2 Sealant joints shall be designed and installed in accordance with ASTM C1193 for joint width, depth, backing, and tooling.
14.1.3 Where the sealant will be painted in service, the chemistry shall be one the coating manufacturer confirms accepts the paint.
14.1.4 Where the sealant contacts a porous substrate that would be stained by plasticizer or fluid migration, the sealant shall be one the sealant manufacturer confirms as non-staining on that substrate, tested to ASTM C1087 or the manufacturer's equivalent staining test.
14.1.5 Where sealant contacts a fluoropolymer coil coating, the Contractor shall obtain the sealant manufacturer's adhesion test data on the actual specified coating and shall apply any primer that data requires.
NOTE Fluoropolymer topcoats are chosen partly because very little sticks to them, which is what keeps them clean, and that same property is why sealant adhesion to them has to be demonstrated on the actual coating rather than assumed from a generic substrate list. (14.1.6)

14.2 Non-Curing Sealant Tapes at Concealed Joints

Concealed Lap and Slip-Joint Sealantradio
● Non-curing butyl sealant tape
○ Non-skinning gunnable butyl sealant
○ Non-curing polyisobutylene sealant tape
Concealed Sealant Tape Minimum Thicknessrange
in
0.03120.06250.093750.1250.18750.25
14.2.1 Non-curing sealant tape shall be installed as the concealed seal at lapped joints, at slip joints, beneath cleats, beneath fasteners passing through a hemmed edge, and behind backer plates at expansion joints.
14.2.2 Non-curing sealant tape shall be installed at full width and without interruption across the sealed path.
NOTE A non-curing tape stays plastic for the life of the joint, so a clamped joint can still slide across it as the metal moves. A cured elastomeric bead in the same location bonds both sides together and converts a moving joint into a restrained one, which is why the two are not interchangeable. (14.2.3)

14.3 Underlayment and Slip Sheets

Underlayment Beneath Sheet Metal on Wood or Sheathing Substratesradio
● Self-adhering polymer-modified bituminous sheet
○ Self-adhering high-temperature polymer-modified bituminous sheet
○ Self-adhering butyl-based high-temperature sheet
○ Mechanically attached synthetic underlayment
○ Rosin-sized building paper slip sheet
○ No separate underlayment because the metal laps a membrane base flashing
Underlayment Minimum Thicknessrange
mil
15202530404560
Underlayment Minimum Side Laprange
in
2346812
Underlayment Minimum End Laprange
in
2346812
14.3.1 Self-adhering polymer-modified bituminous underlayment shall conform to ASTM D1970/D1970M.
14.3.2 Underlayment shall be installed over the full area of wood blocking, sheathing, or deck that receives sheet metal, lapped at not less than the datasheet side and end laps, with all laps rolled.
14.3.3 Where the design surface temperature range in the datasheet reaches the upper end of its range beneath a dark metal surface, the underlayment shall be a high-temperature product rated by its manufacturer for that surface temperature.
14.3.4 Where sheet metal laps a membrane base flashing, a separate underlayment beneath the metal shall not be required, and the cleat or hook strip shall be fastened through the base flashing into structural blocking in accordance with the membrane manufacturer's published detail.
14.3.5 A rosin-sized slip sheet shall be installed between copper or architectural zinc and any bituminous underlayment.

15 Fabrication and Joinery

15.1 Shop Forming and Brake Work

Maximum Shop-Fabricated Piece Lengthrange
ft
810121620243040
Minimum Inside Bend Radius as a Multiple of Metal Thicknessrange
multiples of thickness
0.511.5234
15.1.1 Sheet metal shall be brake-formed in the shop except at closures and end conditions that cannot be dimensioned before adjacent construction is complete.
15.1.2 The maximum piece length shall be as indicated in the datasheet, and shall be further limited by site access, staging area, and handling capability.
15.1.3 Bends shall be formed with the finished face on the outside of the bend where the bend is convex to the finished face.
15.1.4 The inside bend radius shall be not less than the datasheet multiple of the metal thickness, and shall be increased where the coating or metal requires it to avoid fracture.
15.1.5 A coating that has fractured at the apex of a bend shall be cause for rejection of the piece, and the piece shall not be repaired by touch-up.
15.1.6 Cut edges shall be deburred and shall be free of feathered or torn metal.
NOTE Fewer field joints means longer pieces, which means larger trucks, more people on the lift, and more risk of a handling kink that cannot be dressed out. The trade runs in both directions and is settled per project rather than by a universal length. (15.1.7)

15.2 Running Joints in Formed Trim

Running Joint Type Between Expansion Jointsradio
○ Double-lock standing seam
○ Single-lock standing seam
○ Flat-lock seam
○ Lapped joint sealed with concealed tape and a tooled bead
○ Butt joint over a concealed backer plate
○ Soldered flat-lock seam
Minimum Lap at Lapped and Sealed Jointsrange
in
0.511.52346
Minimum Standing Seam Heightrange
in
0.50.7511.52
15.2.1 Running joints shall be of the type indicated in the datasheet, and the joint type for each piece shall be shown on the shop drawings.
15.2.2 Lapped joints shall lap in the direction of water flow, with the upstream piece outside the downstream piece.
15.2.3 Lapped joints shall carry a continuous non-curing sealant tape concealed within the lap and a sealant bead tooled to a clean fillet at the upstream edge.
15.2.4 Standing seams shall be not less than the datasheet height and shall be closed by hand or by a seaming machine matched to the metal and thickness.
15.2.5 Seams shall not be closed by hammering directly on a finished surface.

15.3 Hems, Drip Edges, and Returns

Standard Edge Hemradio
● Single hem folded back on itself
○ Double hem folded twice
○ Open hem with a separate closure strip
○ Hem formed over a continuous stiffener
Standard Hem Depthrange
in
0.250.3750.50.7511.5
Minimum Drip Edge Projection Beyond the Face Belowrange
in
0.250.3750.50.7511.52
15.3.1 Every edge that will be exposed in the finished work shall be hemmed so that no raw cut edge is visible or exposed to weather.
15.3.2 Hems shall be formed at the depth indicated in the datasheet.
15.3.3 Drip edges at copings, fasciae, gravel stops, and through-wall flashings shall project beyond the face below by not less than the datasheet projection.
15.3.4 Drip edges shall be turned downward not less than 30° from horizontal.
NOTE Water leaving a horizontal metal edge follows the underside back toward the wall unless the edge both stands clear of the surface below and points down. A projection with no downturn, or a downturn with no projection, each fails the same way: a stain track down the face below the flashing. (15.3.5)

15.4 Soldered Joints

Solder Alloyradio
● 50/50 tin-lead solder to ASTM B32
○ 60/40 tin-lead solder to ASTM B32
○ 95/5 tin-antimony solder to ASTM B32
○ Tin-silver lead-free solder to ASTM B32
Soldering Fluxradio
○ Zinc chloride acid flux
○ Muriatic acid flux
○ Phosphoric acid flux for stainless steel
○ Rosin flux
Minimum Soldered Seam Widthrange
in
0.50.7511.52
15.4.1 Soldered joints shall be made in copper, lead-coated copper, tin-zinc coated copper, terne-coated stainless steel, and stainless steel at the thicknesses the fabricator's qualification covers.
15.4.2 Solder alloy and flux shall be as indicated in the datasheet, and both shall be confirmed by the solder manufacturer as suited to the base metal being joined.
15.4.3 Where the project prohibits lead-bearing materials, a lead-free alloy of equal or greater joint strength shall be used, and the substitution shall be identified in the submittal.
15.4.4 Seams to be soldered shall be pre-tinned where the base metal or thickness requires it, mechanically locked before soldering, and heated to full flow temperature so that solder is drawn through the seam by capillary action.
15.4.5 Soldered seams shall be not narrower than the datasheet width.
15.4.6 Soldered seams shall be inspected for continuous penetration, and any void shall be reheated and re-soldered.
15.4.7 Flux residue shall be neutralized and washed from both faces of the joint after the joint has cooled.
15.4.8 Zinc-coated steel, aluminum-zinc alloy-coated steel, aluminum, and architectural zinc shall be joined by mechanical seams rather than by soldering.
NOTE Acid flux residue left on the metal keeps working after the joint cools. It holds moisture against the seam, corrodes the base metal under the solder line, and eventually breaks the bond from the inside, so the wash is part of making the joint rather than part of cleaning up after it. (15.4.9)

15.5 Welded Joints in Stainless Steel

15.5.1 Stainless steel joints too heavy to solder, and stainless steel joints where solder appearance is unacceptable, shall be welded by a qualified welder using a process suited to the thickness.
15.5.2 Heat input shall be controlled to limit distortion and to limit sensitization of the heat-affected zone.
15.5.3 Welds in exposed work shall be ground, polished to match the adjacent finish, and passivated.
15.5.4 The Contractor shall submit a welded sample in the specified grade, thickness, and finish for acceptance before welding production pieces.

16 Thermal Movement and Expansion Joints

16.1 Movement Basis

NOTE Every running piece of sheet metal changes length with temperature, and the only question is whether the assembly gives that movement somewhere to go or takes it out on the joints, the cleats, and the fasteners. Restrained metal buckles in heat, tears at joints in cold, and works fasteners loose over thousands of cycles. (16.1.1)
16.1.2 Approximate coefficients of thermal expansion for the metals in this standard are as follows:
Metal Coefficient of thermal expansion
Carbon and zinc-coated steel 6.7 × 10⁻⁶ in/in/°F
Type 316 stainless steel 8.9 × 10⁻⁶ in/in/°F
Type 304 stainless steel 9.6 × 10⁻⁶ in/in/°F
Copper 9.8 × 10⁻⁶ in/in/°F
Aluminum 13 × 10⁻⁶ in/in/°F
Rolled zinc along the rolling direction 19 × 10⁻⁶ in/in/°F
16.1.3 The Contractor shall calculate the movement of each running piece from the metal's coefficient of thermal expansion, the piece length, and the design surface temperature range in the datasheet, and shall show the calculated movement on the shop drawings.
16.1.4 Expansion joint spacing shall be not greater than the value indicated in the datasheet and not greater than the SMACNA Architectural Sheet Metal Manual value for the metal, girth, and design temperature range.
Maximum Spacing Between Expansion Joints in Running Trimrange
ft
68101216202530405060
Expansion Joint Typeradio
○ Slip joint with a concealed backer plate
○ Formed cover plate over an open butt joint
○ Interlocking S-lock joint with a concealed backer plate
○ Bellows joint formed in the metal
Minimum Travel Provided at Each Expansion Jointrange
in
0.250.50.7511.523
Minimum Distance From a Corner to the Nearest Expansion Jointrange
in
61218243648
16.1.5 Each expansion joint shall be of the type indicated in the datasheet and shall provide not less than the datasheet travel in each direction from the installed position.
16.1.6 Expansion joints shall be sealed on the upstream side with non-curing sealant tape.
16.1.7 Cured elastomeric sealant shall not bridge the moving portion of an expansion joint.
16.1.8 Corners shall be solidly joined by mitering, soldering, welding, or a double-lock seam.
16.1.9 Expansion joints shall be located in the running section not closer to a corner than the datasheet distance.
NOTE A corner is the stiffest point in a run of formed metal, so if the nearest joint is at the corner the whole movement of both legs arrives at the one detail least able to absorb it. Moving the joint into the straight run puts the travel where the metal can slide. (16.1.10)

17 Roof Edge Securement to ANSI/SPRI ES-1

17.1 Code Basis for Edge Securement

NOTE ANSI/SPRI/FM 4435/ES-1 sets the wind resistance requirements for metal edge systems on low-slope roofs and defines three test methods. RE-1 evaluates the edge system's ability to restrain an unadhered membrane at the perimeter. RE-2 evaluates resistance to outward horizontal load on gravel stops and fasciae. RE-3 evaluates a coping's resistance to outward horizontal load and to upward load at the building edge. (17.1.1)
17.1.2 Metal edge securement on low-slope roofs shall be designed for the wind loads determined under the building code's structural provisions and shall be tested to the applicable ES-1 test methods.
17.1.3 Edge system components or their packaging shall carry written documentation identifying which components were ES-1 tested, and that documentation shall be delivered to the site with the material.
NOTE Gutters are excluded from the code's edge securement requirement, and gutter anchorage is governed by the gutter provisions of this standard instead. (17.1.4)
Design Wind Pressure at the Roof Perimeter and Corner Zonesrange
psf
20300
Per drawings — structural design criteria (deferred by default)
Safety Factor Applied to the ES-1 Design Pressurerange
multiplier
11.251.51.6722.5
NOTE ES-1 as published does not itself require a safety factor on the design pressure, and industry guidance recommends applying one to cover variability in materials, fabrication, and substrate. The datasheet multiplier is where that decision is recorded, and a multiplier of one records a deliberate decision to design to the tested value with no additional margin. (17.1.5)

17.2 Edge System Compliance Path

ES-1 Compliance Path for Roof-Edge Metalradio
○ Manufactured edge system tested and labeled for the specified profile and securement
○ Shop-fabricated profile tested to ES-1 for this fabricator and this configuration
○ Engineered design sealed by a licensed engineer demonstrating equivalent resistance
FM Approval Required for Roof-Edge Metalradio
○ FM 4435 approval required in addition to the ES-1 listing
○ FM 4435 approval not required
17.2.1 Roof-edge metal shall be provided under the compliance path indicated in the datasheet.
NOTE A tested listing covers one combination of profile, metal, thickness, cleat, fastener type, fastener spacing, and substrate. Substituting any one of those puts the affected length of roof edge outside the listing, whatever the substituted component's own rating is. (17.2.2)
17.2.3 The Contractor shall not substitute any component of a listed edge assembly without a revised listing or a sealed engineering analysis covering the substitution.
17.2.4 Where FM 4435 approval is indicated in the datasheet, the approval listing shall be submitted with the ES-1 documentation.
17.2.5 Where a profile shown in the Contract Documents has no available listing and no test data, the Contractor shall report the condition to the Engineer of Record before fabrication rather than fabricating to the profile and treating it as compliant.

17.3 Nailer and Cleat Anchorage at Roof Edges

Wood Nailer Preservative Treatmentradio
○ Copper-based waterborne preservative
○ Micronized copper preservative
○ Non-copper carbon-based preservative
○ Borate preservative
○ Untreated lumber protected from wetting
17.3.1 The Contractor shall verify in the field that nailer width, thickness, elevation, and attachment match the tested assembly documented in the accepted submittal.
17.3.2 A deviation between the installed nailer or cleat fastener pattern and the tested assembly shall be reported to the Engineer of Record in writing and corrected before edge metal is set over it.
17.3.3 Nailer attachment to the deck or parapet shall not be altered from the tested assembly.
17.3.4 Where the nailer preservative contains copper and the cleat is aluminum or zinc-coated steel, a separation material conforming to the galvanic separation requirements of this standard shall be installed between the cleat and the nailer.
NOTE Copper-bearing waterborne preservatives leave soluble copper and an acidic surface on the lumber. Both attack aluminum, and in a wet exposure a bare aluminum cleat on that lumber shows contact-face corrosion in months rather than years. (17.3.5)

18 Coping

18.1 Coping Geometry and Slope

Coping Transverse Slope Directionradio
● Sloped toward the roof side
○ Sloped toward the exterior face
○ Sloped both ways from a raised center
○ Level across the parapet
Coping Transverse Sloperange
in/ft
00.5
Default: 0.25 in/ft
Coping Overhang Beyond the Exterior Parapet Facerange
in
0.50.7511.5234
Coping Overhang Beyond the Interior Parapet Facerange
in
0.50.7511.5234
NOTE Coping caps the top of a parapet and protects both the wall construction below it and the membrane base flashing terminating on the inside face. (18.1.1)
18.1.2 Coping shall be sloped in the direction and at the rate indicated in the datasheet, achieved by tapering the parapet top or by tapered shims beneath the coping.
18.1.3 Coping shall overhang each parapet face by not less than the datasheet dimension for that face, and both edges shall be hemmed and turned down to form a drip.
NOTE Slope toward the roof side puts coping runoff onto the membrane, where the roof drainage system already handles it. Slope toward the exterior face puts the same water down the wall, which loads the wall's water management and concentrates staining on the visible facade. A two-way slope from a raised center halves the flow on each side and creates two drip lines and two edge details instead of one. A level parapet top holds water on the coping, which loads the joints and fasteners rather than the drainage path. (18.1.4)
18.1.5 Coping is a roof-edge component and shall comply with the roof edge securement requirements of this standard for the design pressure at the parapet edge and corner zones.

18.2 Coping Joinery and Anchorage

Coping Field Joint Type Between Expansion Jointsradio
○ Double-lock standing seam
○ Lapped joint sealed with concealed tape and a tooled bead
○ Butt joint over a concealed backer plate
○ Soldered flat-lock seam
18.2.1 Coping shall be joined between expansion joints by the joint type indicated in the datasheet, with lapped joints running in the direction of slope so that water sheds over the joint rather than into it.
18.2.2 The continuous cleat or hook strip engaging the coping shall be part of the tested edge assembly and shall be fastened at the spacing that assembly requires.
18.2.3 Coping cleat fasteners shall pass through non-curing sealant tape at the nailer.
18.2.4 Corners in coping shall be shop-fabricated as single mitered, soldered, or welded units wherever the corner geometry and shipping allow.
18.2.5 The parapet top shall be verified level and true to the shop drawing dimensions before coping is fabricated, and any deviation exceeding the fabrication tolerance shall be corrected by others before coping is set.

19 Counterflashing at Membrane Base Flashings

19.1 Counterflashing Termination and Lap

Counterflashing Termination at the Wallradio
○ Reglet saw-cut in concrete or unit masonry
○ Manufactured two-piece receiver built into the masonry
○ Termination beneath a through-wall flashing
○ Surface-mounted with a sealed top edge
○ Formed integrally with the coping as a single piece
Counterflashing Minimum Lap Over the Membrane Base Flashingrange
in
23468
Counterflashing Minimum Embedment Into the Reglet or Receiverrange
in
0.50.7511.52
NOTE The membrane base flashing is the water barrier at a roof-to-wall interface. The counterflashing is a removable cover that protects the base flashing's top termination from ultraviolet exposure, debris, and impact, and that can be taken off intact when the roof is replaced. (19.1.1)
19.1.2 Counterflashing shall terminate at the wall by the method indicated in the datasheet, embedded not less than the datasheet depth where it engages a reglet or receiver.
19.1.3 Counterflashing shall lap the top of the membrane base flashing by not less than the datasheet lap.
19.1.4 The lap between counterflashing and base flashing shall not be sealed, and the lap geometry shall carry water down the exposed face of the base flashing.
19.1.5 Counterflashing shall be formed so that any water entering behind it discharges at the bottom of the base flashing onto the roof surface.
19.1.6 Where counterflashing is surface-mounted, its top edge sealant joint shall be designed as a maintained joint, and the maintenance instructions shall identify it as requiring periodic renewal.
19.1.7 A counterflashing termination bar shall not be installed on a horizontal surface.
19.1.8 Reglets shall be cut to the depth the receiver or wedge requires, cleaned of dust and slurry, and shall not be cut through a masonry unit face shell into a cavity.

20 Through-Wall, Head, and Sill Flashings

20.1 Through-Wall Flashing at Masonry

Exposed Metal Drip Component at Through-Wall Flashingsradio
○ Formed metal drip edge lapped beneath the membrane through-wall flashing
○ Formed metal drip edge lapped over the membrane through-wall flashing
○ Fully metal through-wall flashing with soldered or welded laps
○ Membrane through-wall flashing with an integral formed drip
Through-Wall Flashing Drip Projection Beyond the Wall Facerange
in
0.250.3750.50.7511.5
20.1.1 Through-wall flashing shall be installed within the wall at the wall base, at floor lines, at shelf angles, and at the heads and sills of openings, to intercept water in the wall and return it to the exterior at weep openings.
20.1.2 The exposed drip component shall be sheet metal of the type indicated for wall flashing in this standard, lapped with the concealed membrane flashing as indicated in the datasheet.
20.1.3 The exposed drip shall project beyond the wall face by not less than the datasheet projection and shall be turned down not less than 30°.
20.1.4 Where the architectural treatment of the wall face precludes a projecting drip, the metal shall be set flush with the wall face and the concealed flashing above it shall be extended outward to form the drip in front of the wall face.
NOTE A flush metal edge with the flashing above stopping behind the wall face is the condition that produces water tracking back into the wall. Setting the metal flush is workable; stopping the drainage plane short of the face is not. (20.1.5)
20.1.6 Through-wall flashing laps, end dams, and weep spacing shall be coordinated with the masonry scope, and lap and end dam details shall be shown on the sheet metal shop drawings.

20.2 Head and Sill Flashings at Wall Openings

Head Flashing Extension Beyond Each Side of the Rough Openingrange
in
12346
Head Flashing End Dam Minimum Heightrange
in
0.250.511.523
Sill Pan Flashing Configurationradio
○ Formed metal pan with soldered or welded corners
○ Formed metal pan with sealed mechanical corners
○ Formed metal pan with preformed corner boots
○ Formed metal pan with a back leg and end dams turned up from a single sheet
Sill Pan Back Leg Minimum Heightrange
in
0.250.511.5234
20.2.1 Head flashing shall be continuous over the opening, lapped over the top of the frame, and turned up behind the wall water-resistive barrier so that water on the barrier is carried over the flashing and discharged beyond the frame.
20.2.2 Head flashing shall extend beyond each side of the rough opening by not less than the datasheet extension.
20.2.3 Head flashing shall have an end dam at each end, not less than the datasheet height, formed and sealed against the flashing's back leg.
20.2.4 Sill pan flashing shall be continuous below the rough sill, lapped over the water-resistive barrier below, and turned up at the back and at both ends in the configuration indicated in the datasheet.
20.2.5 The sill pan back leg shall be not less than the datasheet height.
20.2.6 Sill pan flashing shall be installed before the window or door unit is set.
NOTE A head flashing without end dams discharges off its own ends into the wall cavity, which is the same result as having no head flashing at the jambs. A pan retrofitted after the unit is set cannot be turned up behind the frame, so it collects water it has no way to release. (20.2.7)

21 Gutters, Downspouts, and Scuppers

21.1 Gutter Profile, Sizing, and Slope

Gutter Profileradio
○ K-style ogee gutter
○ Half-round gutter
○ Box gutter
○ Built-in gutter set within the roof edge
○ Fascia-integrated gutter
Gutter Cross-Section and Outlet Sizingtext
Enter value...
Per drawings — roof drainage calculation (deferred by default)
Gutter Slope to the Outletrange
in/ft
00.5
Default: 0.125 in/ft
Gutter Hanger Maximum Spacingrange
in o.c.
1216182430323648
21.1.1 Gutter cross-section, front and back heights, outlet size, and outlet spacing shall be established by the Engineer of Record from a roof drainage calculation using the contributory roof area and the design rainfall intensity required by the building code, and shall be as indicated in the datasheet.
21.1.2 The Contractor shall confirm the fabricated gutter cross-section against that calculation before releasing gutters for fabrication.
21.1.3 Gutters shall be sloped to the outlets at not less than the rate indicated in the datasheet.
NOTE Slope moves standing water to the outlet, which limits the residence time of debris, ice, and dissolved salts against the gutter's seams. At zero slope a gutter still drains, but only through the hydraulic gradient of the water itself, so construction tolerance and deflection between hangers set where the water actually stands. Visible slope against a level fascia line is the cost of a steeper rate on a long run. (21.1.4)
21.1.5 Gutters shall be supported at not more than the datasheet hanger spacing.
21.1.6 Hangers shall be of a metal compatible with the gutter and shall engage the outer rim from above.
21.1.7 Hangers shall not penetrate the bottom or inner face of the gutter.
21.1.8 Hangers shall be designed for the weight of the gutter filled to the overflow line, plus the snow and ice load determined for the project.

21.2 Gutter and Downspout Joinery

Gutter Running Joint Methodradio
○ Soldered lap joint
○ Welded lap joint
○ Lapped joint sealed with concealed tape and a tooled bead
○ Slip joint with a concealed backer plate at expansion joints and sealed laps between
Minimum Downspout Lap at Jointsrange
in
0.511.5234
Downspout Strap Maximum Spacingrange
ft
34568101215
21.2.1 Gutter running joints shall be made by the method indicated in the datasheet, and the method shall be one the selected gutter metal accepts.
21.2.2 Gutter end caps shall be of the gutter metal, formed to the gutter profile, and joined to the gutter by the same method as the running joints.
21.2.3 Gutter expansion joints shall be provided at not more than the expansion joint spacing indicated in this standard for the gutter metal.
21.2.4 Downspout joints shall lap in the direction of flow, upper piece outside, by not less than the datasheet lap.
21.2.5 Downspouts shall be anchored to the wall at not more than the datasheet strap spacing, with straps of the downspout metal or a compatible metal not less noble than it.
21.2.6 Downspouts shall discharge to the collection point shown in the Contract Documents, as indicated on the contract documents.
21.2.7 Downspout discharge at a below-grade outlet shall be coordinated with Below Grade WaterproofingBelow-Grade WaterproofingResolves to the current adopted revision.sync/below-grade-waterproofing.

21.3 Scuppers, Conductor Heads, and Overflow

Through-Wall Scupper Constructionradio
○ Formed metal sleeve with soldered or welded corners
○ Formed metal sleeve with sealed mechanical corners
○ Formed metal sleeve with an integral flange lapped by the roof membrane
○ Not applicable because the roof edge has no through-wall scupper
Secondary Drainage Provision Served by This Scoperadio
○ Overflow scuppers through the parapet
○ Overflow conductor heads with an overflow lip
○ Open roof edge providing secondary drainage without a parapet
○ Not applicable because secondary drainage is provided by piped overflow drains
21.3.1 Through-wall scupper sleeves shall be fabricated by the method indicated in the datasheet, with a flange on the roof side lapped into the membrane assembly and a formed drip on the exterior face.
21.3.2 Scupper sleeves shall be fabricated as single units where the wall thickness allows, without a joint within the wall.
21.3.3 Conductor heads shall be sized to receive the design flow from the scupper or transition piece serving them, formed of the metal indicated for gutters and downspouts, and provided with an overflow lip on the open face that discharges outward.
21.3.4 The secondary drainage provision indicated in the datasheet shall be coordinated with the roof drainage design, and the elevation of every overflow opening shall be verified in the field before the sleeve is fabricated.

22 Expansion Joint Covers at Walls and Parapets

NOTE A building expansion joint separates structures that move independently, and it crosses the envelope at the wall, at the parapet, and onto the roof. The cover has to accommodate that movement and stay weathertight through the full range, and the transitions between planes are where it usually does not. (22.1)
Wall Expansion Joint Cover Typeradio
○ Manufactured cover assembly with a preformed bellows and metal trim
○ Shop-fabricated metal cover over an elastomeric bellows
○ Composite metal and membrane cover
○ Formed metal cover with a concealed slip joint
Design Movement at the Building Expansion Jointtext
Enter value...
Per drawings — structural drawings (deferred by default)
22.2 The expansion joint cover shall accommodate the design movement indicated in the datasheet without loss of weathertightness at either extreme of travel.
22.3 The sheet metal portion of the cover shall be of the metal indicated for wall flashing in this standard and shall be lapped or sealed to adjacent flashing so that water on the wall drainage plane is carried past the joint.
22.4 The cover shall run continuously from the wall plane onto the roof plane, and the transition shall be made without a break in the water-shedding path.
NOTE A cover that stops at the wall-to-roof transition and restarts on the roof leaves the corner of the joint - the point of largest combined movement - as an open seam behind two independent assemblies. (22.5)

23 Galvanic Separation of Dissimilar Metals

23.1 Separation Method and Extent

Dissimilar Metal Separation Methodradio
○ Elastomeric gasket at the full contact area
○ Non-curing sealant tape at the full contact area
○ Polyethylene or polyolefin separation sheet
○ Barrier coating applied to the contact face
○ Non-metallic isolating washers and bushings at fasteners
Elastomeric Separation Gasket Minimum Thicknessrange
in
0.030.06250.093750.1250.18750.25
NOTE In the architectural galvanic series, running from most anodic to most cathodic, the order is zinc, aluminum, zinc-coated steel, carbon steel, lead, copper alloys, and stainless steel. The metal nearer the anodic end corrodes to protect the one nearer the cathodic end, and the rate depends on how much cathode area is coupled to how little anode area. (23.1.1)
23.1.2 Separation shall be provided wherever metals separated in the galvanic series are in direct contact, are coupled by water draining from one onto the other, or are connected through a shared fastener.
23.1.3 Separation shall be by the method indicated in the datasheet, installed across the full contact area without gaps.
23.1.4 Elastomeric separation gaskets shall be not thinner than the datasheet thickness.
23.1.5 Copper and copper alloy surfaces shall not drain onto aluminum, architectural zinc, zinc-coated steel, or carbon steel unless a continuous separation layer intercepts the runoff.
23.1.6 Zinc-coated steel and architectural zinc shall be separated from fresh mortar, fresh concrete, and copper-bearing runoff.
23.1.7 Aluminum shall be separated from fresh mortar, fresh concrete, and copper-bearing preservative-treated lumber.
23.1.8 Stainless steel fasteners through aluminum, zinc-coated steel, or architectural zinc shall carry a bonded sealing washer at the penetration.
23.1.9 Where a historically coated product such as lead-coated copper, tin-zinc coated copper, or terne-coated stainless steel is used, the Contractor shall obtain the producer's written compatibility requirements for every metal it will contact and shall submit them before fabrication.

24 Installation Sequencing and Substrate Acceptance

24.1 Sequence With the Roofing and Wall Trades

NOTE The sheet metal scope interleaves with the roofing scope at every roof-to-wall, roof-to-curb, and roof-edge interface, and with the wall scope at every flashing that a cladding material laps. (24.1.1)
24.1.2 The installation sequence shall follow the order below unless the pre-installation conference establishes a different order in writing for a specific condition:
  • Wood nailers and blocking at roof edges and parapet tops are installed and inspected before the roofing membrane.
  • The roofing Contractor installs the membrane field, the base flashings up the inside face of the parapet, and any edge components furnished as part of a warranted roof assembly.
  • Base flashings are completed and probed before counterflashings, copings, gravel stops, and fasciae are set over them.
  • Wall flashings are installed before the cladding that laps them, and gutters, downspouts, and trim follow the cladding.
24.1.3 The pre-installation conference shall record any condition where this order is altered, together with the reason and the responsible trade for each affected piece.
24.1.4 Where a coping or edge component is furnished under a cladding or panel scope, the interface between that piece and the sheet metal in this scope shall be detailed on the sheet metal shop drawings.

24.2 Substrate Acceptance

24.2.1 The installer shall inspect every substrate before installing sheet metal over it and shall verify that nailers are fastened, of the specified dimension and treatment, and at the correct elevation and width; that membrane base flashings are fully adhered and probed where they will be lapped; that masonry is at the dimensions shown with reglets cut clean to the specified depth; and that supporting framing for gutters and conductor heads is in place at the correct elevation.
24.2.2 Deficient substrate conditions shall be reported to the General Contractor in writing before work proceeds in that area.
24.2.3 Sheet metal shall not be installed over a non-conforming substrate.
24.2.4 Where the parties disagree whether a substrate condition is conforming, the Engineer of Record shall make the initial determination.
24.2.5 The cost of correcting a substrate condition reported in writing before installation shall be borne by the trade responsible for the substrate; the cost of removing and reinstalling sheet metal set over a condition that was not reported shall be borne by the sheet metal Contractor.

24.3 Field Cutting and Fitting

24.3.1 Field cutting shall be limited to end conditions, penetrations, and irregular corners that could not be dimensioned before adjacent construction was complete.
24.3.2 Field cuts shall be made with snips, hand shears, or a powered nibbler or shear that does not heat the metal.
24.3.3 Abrasive cutting wheels and abrasive saws shall not be used on coated or polished sheet metal.
24.3.4 Field-cut edges shall be deburred and shall receive the touch-up treatment specified for cut edges.

25 Field Testing and Inspection

25.1 Water Testing of Completed Flashings

Field Water Test of Completed Wall Flashingsradio
○ First-of-type test on each flashing type before that type is produced in quantity
○ Test at locations selected by the Engineer of Record during construction
○ Test on a percentage of installed locations selected at random
○ Not required
Water Test Spray Duration at Each Test Locationrange
minutes
5101520304560
Proportion of Installed Locations Tested Where Random Testing Is Selectedrange
%
125101525
25.1.1 Field water testing shall be performed at the frequency indicated in the datasheet, using a spray applied in accordance with AAMA 501.2 or an equivalent method the Engineer of Record accepts.
25.1.2 Each test location shall be sprayed for not less than the datasheet duration.
25.1.3 The interior side of each test location shall be observed continuously during the test and for fifteen minutes after the spray stops.
25.1.4 Water appearing on the interior side shall be cause for rejection of that location, and the cause shall be identified before the location is repaired.
25.1.5 The Contractor shall bear the cost of retesting a location that failed, and of testing the additional locations the Engineer of Record selects following a failure.

25.2 Inspection at Substantial Completion

25.2.1 The sheet metal work shall be jointly inspected at substantial completion by the Contractor, the Engineer of Record, and the Owner's representative.
25.2.2 The inspection shall verify that every piece is in its final position; that joints are formed and sealed as detailed; that no cured sealant bridges the moving portion of an expansion joint; that roof-edge metal matches the tested assembly in profile, cleat, fastener type, and fastener spacing; that flashings lap and shed water in the design direction; that gutters are sloped and clear; that downspouts are anchored and discharge as detailed; that dissimilar-metal separation is in place; and that finished surfaces are clean and undamaged.
25.2.3 Deficiencies identified at the inspection shall be corrected before the Contractor's warranty period begins.

26 Delivery, Storage, and Handling

26.1 Protection of Coil, Sheet, and Formed Pieces

Maximum Time Protective Film May Remain on Installed Metalrange
days
30456090120180
26.1.1 Coil, sheet, and formed pieces shall be stored on edge or on spacers, off the ground, under cover, in a dry and ventilated location.
26.1.2 Pieces shall not be stacked flat with weight bearing on the finished face.
26.1.3 Water shall not be allowed to stand between stacked sheets or nested pieces.
26.1.4 Protective film shall remain in place through fabrication and installation and shall be removed at substantial completion, and in no case later than the datasheet duration after installation.
26.1.5 The Contractor shall confirm the film manufacturer's maximum exposure period and shall report to the Engineer of Record where the construction schedule would exceed it.
NOTE Film left on a surface past its exposure limit bonds to the coating under ultraviolet exposure and heat, and comes off in fragments or takes coating with it. Water trapped between stacked sheets produces white corrosion on zinc-bearing coatings and staining on coil coatings that no cleaning method removes. (26.1.6)

27 Cleaning and Protection

27.1 Cleaning of Installed Sheet Metal

27.1.1 Installed sheet metal shall be cleaned at substantial completion of construction debris, sealant residue, mortar residue, and protective film.
27.1.2 Cleaning shall use potable water and a detergent with a pH between 5 and 9, applied with a soft cloth or sponge and rinsed with potable water.
27.1.3 Solvents, acidic cleaners, alkaline cleaners, abrasive cleaners, and abrasive pads shall not be used on coated or polished surfaces.
27.1.4 Mortar or grout contacting a coated surface shall be flushed off with water before it sets.
27.1.5 Cured mortar shall be removed mechanically with a plastic or wood scraper.
27.1.6 Acid washing of adjacent masonry shall not be performed until sheet metal in the wash path has been masked and protected.
NOTE Wet mortar on a coil coating etches the film while it cures, so a smear removed the next morning leaves a permanent mark even when the mortar itself comes away cleanly. The time window is minutes, not hours. (27.1.7)

28 Warranty

28.1 Contractor Workmanship Warranty

Contractor Workmanship Warranty Termrange
years
123510
28.1.1 The Contractor shall provide a written workmanship warranty for the term indicated in the datasheet, running from the date of substantial completion.
28.1.2 The warranty shall cover defects in fabrication, joinery, anchorage, and installation, including water entry at sheet metal joints and displacement under the design wind pressure.
28.1.3 The Contractor shall bear the cost of repair, of access to the repair location, and of repairing collateral damage caused by the defect or by the repair.
28.1.4 Where a warranted repair is made, the repaired work shall carry a warranty for a full term from the date of the repair, or for the remainder of the original term, whichever is longer.
28.1.5 The Contractor's warranty is in addition to the finish manufacturer's warranty and does not replace it.

28.2 Finish Manufacturer Warranty

Finish Warranty Term for Film Integrityrange
years
510152025303540
Finish Warranty Term for Color Change and Chalkrange
years
510152025303540
Maximum Color Change Over the Warranty Termrange
ΔE units
23456810
Minimum Chalk Rating to ASTM D4214 at the End of the Warranty Termselect
No. 4
No. 6
No. 8
28.2.1 The finish manufacturer shall provide a written warranty for the terms indicated in the datasheet, covering film integrity, color change, and chalk on the specified coating and color.
28.2.2 Color change over the warranty term shall not exceed the datasheet limit, measured to ASTM D2244 on a cleaned surface compared against an unexposed retained sample.
28.2.3 Chalk at the end of the warranty term shall be not less than the datasheet rating when evaluated to ASTM D4214.
28.2.4 The Contractor shall identify any project condition that falls within an exclusion in the finish manufacturer's warranty, and shall obtain the manufacturer's written position on that condition before the coating is ordered.
NOTE Marine spray, industrial fallout, agricultural ammonia, standing water, and chemical exposure are the exclusions that most often apply to a real site, and a coating ordered without checking them can arrive with a warranty that excludes the very exposure it was selected for. (28.2.5)

28.3 Roof-Edge Assembly Warranty

28.3.1 Where roof-edge metal is furnished as part of a warranted membrane roof assembly, the Contractor shall confirm in writing that the membrane manufacturer's warranty covers the edge metal on the same terms as the membrane.
28.3.2 Where roof-edge metal is furnished by an edge system manufacturer under its own warranty, the Contractor shall obtain that warranty and submit it at closeout.
28.3.3 The Contractor shall confirm before the edge product is ordered that the product is accepted by the membrane manufacturer for use with the warranted assembly.

29 Spare Materials

Touch-Up Material Delivered to the Owner per Specified Colorrange
quarts
12468
Spare Formed Trim Delivered as a Proportion of Installed Lengthrange
%
123510
Spare Components Delivered to the Ownercheckbox
☑ Touch-up material in each specified color
☐ Spare formed trim in each specified profile
☑ Spare gutter hangers and downspout straps
☐ Spare cleat stock in each metal and thickness
☐ Spare sealant in each specified chemistry and color
29.1 The Contractor shall deliver the spare components indicated in the datasheet to the Owner at substantial completion.
29.2 Spare material shall be from the same production lot as the installed work wherever the lot remains available.
29.3 Spare material shall be delivered in sealed, labeled containers or wrapped bundles identifying the metal, thickness, finish system, color, and lot.
29.4 The Contractor shall obtain the Owner's written receipt for spare material delivered.