A Class A roof is one whose covering, or whole assembly, earned the highest fire rating in the ASTM E108 or UL 790 fire tests, meaning it resists severe fire exposure from outside, including burning brands landing on it. In Colorado’s wildfire areas it is the baseline: the 2025 Colorado Wildfire Resiliency Code requires a Class A covering or assembly on every mapped parcel, low, moderate or high. The code also requires two details many roofs skip: the gap under tile or metal profiles must be blocked against embers, and valleys need metal flashing over a wide cap sheet. This page is general information; the product listing and your building department decide what passes.
On this page: The rating · Covering vs assembly · Materials · Valleys and gaps · Checklist
What Class A actually tests
ASTM E108 and UL 790 are the standard fire tests for roof coverings. They expose a roof sample to flame and to burning brands, and rate it Class A, B or C, with Class A for severe exposure. The model residential code, the International Residential Code, has long required Class A, B or C roofing where local law calls for it or where the roof edge is less than 3 feet from a lot line, tested to those same standards. Colorado’s wildfire code sets the bar at Class A for every class of WUI parcel.
Local rules can go further. In the City of Colorado Springs, the Pikes Peak Regional Building Department reroof rules already require Class A on one- and two-family homes and exclude solid wood roofing; our Colorado Springs roofing codes guide covers that, and our cedar shake fire hazard page covers replacing wood roofs.
Covering or assembly
Some products are Class A by themselves. Others are Class A only as an assembly, tested over a particular underlayment, cap sheet or deck. The Colorado code accepts either: a “roof covering or roof assembly classified as Class A.” The practical difference is installation. If a product’s Class A rating depends on a listed underlayment, swapping that underlayment for a cheaper one can void the rating, even though the visible roof looks the same. Ask for the listing and keep a copy with your permit records.
Common roofing materials and the Class A question
Ratings vary by product, so treat this as a list of questions to ask, not a list of answers:
| Material | Question for the listing | What else to check on the roof |
|---|---|---|
| Fiberglass asphalt shingles | Is this exact shingle Class A on its own? | Nothing beyond normal install, if it is |
| Standing seam or exposed-fastener metal | Is it Class A alone or only over a listed underlayment? | How the space under ribs or panels is closed |
| Stone-coated steel | Which battens and underlayment does the listing require? | The space the battens create above the deck |
| Concrete or clay tile | Is the listing for the tile alone or an assembly? | Open ends at the eave and ridge |
| Synthetic shake or slate | Which cap sheet or underlayment makes it Class A? | That the named layer is actually installed |
| Wood shakes | Is there any Class A listing at all? | Local bans, such as in Colorado Springs |
If you are weighing a Class 4 impact-rated shingle for hail, see our guide on whether a Class 4 roof is worth it. Impact and fire ratings are separate tests; a good WUI roof in the Pikes Peak region usually has both.
Valleys and hidden gaps
Two parts of the code catch roofs that are otherwise Class A:
- Profiled roofs (section 403.2.1). Where the covering’s shape leaves a space above the deck, as with barrel tile, some metal panels and batten-set stone-coated steel, that space must resist flames and embers. The options are firestopping it with noncombustible material, laying one layer of ASTM D3909 cap sheet over the combustible deck, or using a listed Class A assembly.
- Valleys (section 403.2.2). Valley flashing must be corrosion-resistant metal at least 0.019 inch thick (26-gauge galvanized) over a cap sheet underlayment complying with ASTM D3909, at least 36 inches wide and running the full valley length. Valleys collect needles and leaves, and that debris is where embers settle.
A Class A reroof checklist
- Confirm whether your parcel is mapped and its class, using our Colorado Wildfire Resiliency Code guide.
- Choose a covering with a Class A listing and note whether it is a covering or assembly rating.
- Specify the listed underlayment or cap sheet, and how profiled gaps will be closed.
- Specify metal valleys over a 36-inch D3909 cap sheet.
- Pair the roof with ember-resistant vents and noncombustible gutters. See our guides to vents and gutters.
- Keep the listings with the permit and final inspection records.
For the bigger picture, start at the wildfire home hardening guide.
Getting a Class A roof installed
Integrity Roofing and Painting is a veteran-owned, family-run roofer in Colorado since 1990 and an Owens Corning Platinum Preferred contractor, with 650+ Google reviews. We install asphalt, metal, stone-coated steel and tile roofs across the Front Range, from Monument and Black Forest to Golden, and we write the listed underlayment and valley details into the estimate. Our standard roof valley detail meets the code. Call (719) 488-2800 for a free Colorado Springs inspection or (303) 209-0152 for a free Denver inspection. Metal options are on our Colorado Springs metal roofing page.
Sources: 2025 Colorado Wildfire Resiliency Code, section 403.2 (DFPC); ASTM E108, Fire Tests of Roof Coverings (scope); International Residential Code 2021, section R902.1 (UpCodes viewer); IBHS, 2007 Witch Creek and Poomacha Fires claims analysis; Colorado State Forest Service, Protect your home and property.
