Sheet metal trim warranties are more complex than they appear. A single coping cap installation involves three distinct warranty types — coating, substrate, and installation — each provided by a different party and covering different failure modes. Understanding which warranty covers what, what voids coverage, and how to write warranty language that is actually enforceable is essential to protecting the owner's long-term interests.
The Three Warranty Types in Sheet Metal Trim
| Warranty Type | Provided By | Covers | Typical Duration |
|---|---|---|---|
| Coating warranty | Coil coating manufacturer | PVDF coating fade, chalk, adhesion failure | 30 years (PVDF/AAMA 2605) |
| Substrate warranty | Metal coil manufacturer | Corrosion perforation of base metal | 20–25 years (Galvalume); varies for aluminum |
| Installation warranty | Sheet metal subcontractor | Workmanship defects — improper lapping, fastening errors, water infiltration | 2 years (AIA default); 5–10 years if specified |
The most common mistake architects make in warranty specification is addressing only one of these three — typically the coating — and leaving the installation warranty at the 2-year AIA default. An owner whose coping cap fails at year 3 due to improper clip spacing may find themselves outside their installation warranty coverage.
Coating Warranties: PVDF and AAMA 2605
The Kynar 500 (PVDF) coating warranty is the most frequently cited in architectural sheet metal specs. Here is what architects need to know about the structure of this warranty:
What the 30-Year PVDF Warranty Covers
PVDF coating warranties are performance-based warranties tied to AAMA 2605 test criteria. They cover:
- Color fade: Color change (ΔE) shall not exceed 5 units after 10 years South Florida exposure (measured per ASTM D2244)
- Chalking: Chalk rating shall not exceed 8 (ASTM D4214) after 10 years South Florida exposure
- Adhesion: Coating shall not peel, blister, or delaminate from the substrate for 30 years under normal atmospheric exposure
The warranty does not cover: physical damage (denting, scratching), incompatible cleaning chemicals, ponding water, or performance of the substrate metal itself.
Warranty Exclusions to Watch For
PVDF coating warranties typically exclude:
- Cut edge corrosion: On steel substrates, rust wicking from cut edges inward is the most common warranty void. Cut edges must be treated with a compatible primer or edge sealer, or the warranty excludes edge corrosion entirely. This is why coastal projects should use aluminum substrate instead of steel — aluminum does not rust at cut edges.
- Incompatible contact: Direct contact with certain sealants (acetoxy-cure silicone), copper, and lead can stain or degrade PVDF coatings and void the warranty.
- Improper installation: If the material is installed contrary to the manufacturer's installation guidelines, the warranty is void. This connects directly to the importance of proper submittals and installation quality control.
- Environmental exclusions: Some warranties exclude industrial environments with high atmospheric acid (within a certain distance of heavy industrial facilities), or severe marine environments.
Coastal note: Many PVDF warranties have a coastal exclusion zone (typically 1,500–5,000 feet from the ocean) for steel substrates. For coastal applications, specify PVDF-coated aluminum, which typically carries no coastal exclusion, and verify with the specific coating manufacturer that their warranty applies to the project's location.
Substrate Warranties: Galvalume and Aluminum
Galvalume Steel Substrate
Galvalume (ASTM A792) steel is typically warranted by the steel mill against corrosion perforation for 20–25 years when used in architectural applications. The substrate warranty requires:
- Installation per the Galvalume manufacturer's application guidelines
- No direct contact with cement, mortar, or concrete (galvanic reactions accelerate corrosion)
- No contact with copper (copper ions carried in runoff attack Galvalume)
- No contact with pressure-treated lumber containing copper azole or ACQ preservatives
- Cut edges must be protected from standing water
Aluminum Substrate
Aluminum sheet (ASTM B209) does not have the same corrosion perforation concern as steel — aluminum forms a protective oxide layer that prevents through-wall corrosion under most conditions. Aluminum coil suppliers typically offer limited warranties against "significant" corrosion under normal atmospheric conditions, but the warranty terms are less standardized than Galvalume warranties. The practical benefit of aluminum for architects is that the substrate warranty exclusions are fewer and the coastal exposure restrictions are eliminated.
Installation Warranties: What to Specify
The AIA A201 General Conditions default warranty period is 1 year from Substantial Completion for construction defects. This is inadequate for sheet metal trim — many installation defects (improper lap, incorrect clip spacing) manifest only after the first significant wind event or after the first winter's thermal cycling.
Best practice for Division 07 sheet metal warranty specification:
A. Special Warranty — Sheet Metal Trim Installation: Provide contractor's written warranty, signed by the sheet metal subcontractor, covering defects in materials and workmanship for 5 years from Substantial Completion. Warranty shall include:
1. Water infiltration through any joint, seam, or fastener penetration in sheet metal trim due to defective workmanship
2. Failure of any clip, cleat, or fastener anchorage due to improper installation
3. Buckling or distortion of trim sections due to improper installation
B. PVDF Coating Warranty: Submit manufacturer's 30-year limited coating warranty per AAMA 2605. Warranty shall cover: color fade exceeding 5 ΔE units (10 years), chalk exceeding rating 8 (10 years), and coating adhesion failure.
C. Substrate Warranty: Submit coil manufacturer's 20-year limited warranty against corrosion perforation of base metal, applicable to the project location.
D. Warranty commencement: Date of Substantial Completion unless otherwise specified.
E. All warranties shall name the Owner as warranted party.
Roofing System Warranty and Coping Cap Compatibility
When a roofing membrane manufacturer provides a system warranty (especially an NDL — No Dollar Limit — warranty), the warranty typically requires that all components at the roof edge, including coping caps, meet the manufacturer's specific requirements. This can affect:
- Coping cap system type: Some membrane manufacturers require ANSI/SPRI ES-1 tested coping systems. If the coping cap is custom-fabricated and not tested to ES-1, the roofing system warranty may not cover edge-related leaks.
- Installer certification: Some NDL warranties require that the coping cap installer be certified by the membrane manufacturer.
- Sealant type: The membrane manufacturer may specify which sealants are compatible with the membrane at the coping cap base flashing junction.
When specifying roofing system warranties, confirm with the membrane manufacturer early in the design process what coping cap requirements apply. Coordinate these requirements with the Division 07 coping cap specification so that both the coping cap and membrane spec are consistent.
Warranty Documentation at Closeout
At project closeout, the following warranty documents should be collected for the owner's operations file:
- Sheet metal subcontractor's installation warranty letter (signed, dated, naming the Owner and project)
- PVDF coating manufacturer's warranty certificate (typically requires registration within 60 days of installation)
- Galvalume or aluminum substrate warranty certificate
- Roofing system manufacturer's warranty certificate (if applicable, covering the edge/coping system)
- Color samples and coating product data sheets (for future reference in the event of color-matched repair)
Failure to register the PVDF coating warranty with the coating manufacturer within the registration window (typically 60–90 days from installation) often voids the warranty. Include a reminder in the project closeout checklist.
← Back to Spec Hub · CSI MasterFormat Guide →
Frequently Asked Questions
What is the typical warranty length for Kynar (PVDF) coated sheet metal?
Kynar 500 (PVDF) coatings meeting AAMA 2605 carry a 30-year limited warranty from the coil coating manufacturer against excessive fade, chalk, and adhesion loss. Key terms: chalk rating shall not exceed 8 (ASTM D4214) after 10 years South Florida exposure; color fade shall not exceed 5 ΔE units after 10 years. The substrate manufacturer provides a separate corrosion warranty (typically 20–25 years for Galvalume steel).
What is the difference between a coating warranty and a substrate warranty?
A coating warranty covers the performance of the PVDF film — fade, chalk, adhesion failure. A substrate warranty covers the base metal against corrosion perforation. For Galvalume steel, the substrate warranty is typically 20–25 years. For aluminum, the substrate warranty terms are less standardized. Both warranties are needed for complete coverage of an architectural coping cap.
What voids a sheet metal coating warranty?
Common voiding conditions include: cut edges left exposed on steel substrates (rust wicking voids the edge area), contact with incompatible sealants (acetoxy-cure silicone), ponding water on horizontal surfaces, caustic or abrasive cleaners, physical damage, and installation contrary to manufacturer's guidelines. For coastal projects, confirm whether the warranty has a coastal exclusion zone for steel substrate — if so, use aluminum.
How long should an installation warranty be for sheet metal trim work?
The AIA A201 default is 1 year, which is inadequate for sheet metal. Most Division 07 specs require 5 years for sheet metal installation warranty. The warranty should cover water infiltration through any joint or fastener, clip or cleat failure, and buckling from improper installation. It is provided by the sheet metal subcontractor, named to the Owner.
Does a roofing system warranty cover the metal coping cap?
Roofing system warranties vary — some NDL warranties cover the edge/coping system if it meets the manufacturer's specific requirements (including ANSI/SPRI ES-1 testing and installer certification). Others do not cover the coping at all. Confirm with the membrane manufacturer early in design what coping requirements apply to maintain the roofing system warranty, and coordinate these into the Division 07 coping specification.