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Solar on a Class A roof
A photovoltaic array does not inherit the roof’s Class A letter. Class A, B, and C attach to a tested covering-on-deck under ASTM E108 or UL 790. FEMA P-737 says building-integrated or rooftop PV should meet Class A, NFPA 70, and the site wind loads, that penetrations need noncombustible caulk, flashing, or assemblies, and that extra screening under the array can hurt panel temperature. Oregon R327 does not name solar. This page does not invent UL 2703 numbers.
You are on a Class A roof looking at rails, standoffs, and a dark gap under the modules. Needles sit in that gap. That is a debris trap and a penetration field, not a second shingle.
No g3-passed solar-on-roof exhibit exists. See covering versus assembly for the class letter. Do not use a house-level hub graphic as this array.
Why it matters
Embers collect under racks the way they collect in tile tunnels. A roof that passed E108 without the array is not the same assembly with the array. Penetrations are holes. See wall penetrations for the same sealing idea on walls.
How the jobs split
| Job | What decides it | What it is not |
|---|---|---|
| Roof covering class | E108/UL 790 assembly, R327.3 Class B floor in Oregon | The panel SKU |
| Array as equipment (FEMA) | Class A, NFPA 70, ASCE 7-22 wind. Flush or BIPV preferred | Mesh stuffed under the modules |
| Penetrations | Noncombustible caulk, flashing, or assemblies | Unsealed conduit |
| Debris | Keep the covering clear. IBHS Class A covering plus maintenance | A listing that never gets cleaned |
The paths
1. Keep the roof class honest. Write the covering, underlayment, and deck. See how to read a Class A roof listing. Oregon’s floor is Class B-rated assembly equivalent where R327 is adopted. IBHS Base still asks for Class A covering.
2. Follow FEMA’s solar row when you use that guide. Class A, electrical code, wind. Flush or BIPV to cut debris. Protect every roof penetration. Do not add extra screens or baffles that trap heat. Ballasted arrays are a wind and wildfire problem in that guide.
3. Do not cite UL 2703 here. The catalog named it. This session did not open that standard. If the official wants it, open the live document.
4. California. CWUIC is a different book. Do not paste Oregon’s silence on solar onto a mapped California lot as permission.
What people mix up
- “The roof is Class A, so the solar is Class A.”
- Screening the array like a vent.
- Leaving standoff holes unsealed.
- Treating R327 as a solar listing program.
How to check
- Name the roof assembly without the array, then ask what document covers the array.
- Look under the modules for debris traps.
- Look at every penetration. Caulk, flashing, or a listed assembly, not daylight.
- If someone specifies extra mesh under the rails, read FEMA’s temperature warning.
Limits
This page does not spec a racking SKU or an electrical one-line. It does not open UL 2703. FireApproved is not the AHJ. FEMA P-737 is a builder guide. IBHS is a designation.
Related records
Questions
If the shingles are Class A, are the panels Class A?
No. Class A, B, and C attach to a tested roof assembly of covering on deck. FEMA says building-integrated or rooftop PV should meet Class A, NFPA 70, and ASCE 7-22 wind loads. That is a builder-guide stack, not a free inheritance from the shingle bag.
Can I add mesh under the panels to catch embers?
FEMA says no additional screening or baffles should be installed, because they may affect the panel’s ability to stay at a safe temperature. Flush or BIPV mounting reduces debris under the array. Do not invent a mesh product this page did not open.
Does Oregon R327 require listed solar?
R327.3 names roof coverings and profile gaps. It does not print a solar subsection. Penetrations still exist as holes. Confirm with the official. UL 2703 is not opened on this page.