What class are architectural shingles?
Fire class
Class A is the highest fire rating for roof coverings, tested under ASTM E108 or UL 790. Fiberglass-mat asphalt shingles almost universally achieve it when installed as the manufacturer specifies.
Wind classes
- ASTM D3161 blows air across the shingle with a fan. Class A is tested at 60 mph, Class D at 90 mph, and Class F, the top rating, at 110 mph.
- ASTM D7158 measures uplift resistance of the sealed shingle. Class D corresponds to 90 mph, Class G to 120 mph, and Class H to 150 mph.
These ratings assume the shingle is sealed and nailed correctly. Real wind performance depends on installation, especially nail placement and starter strips at the edges.
Impact class
UL 2218 drops steel balls from 1 1/4 to 2 inches in diameter onto the shingle. Class 4 means it survived the 2-inch ball without cracking through. Many standard architectural shingles are not impact rated at all. For example, GAF's Timberline HDZ is Class 3 on labeled packages, while Timberline UHDZ with UltraMat is Class 4. Insurance discounts for impact resistance in Georgia generally require Class 4.
How to check yours
The bundle wrapper lists the standards the shingle meets. If the roof is already on, look for leftover bundles in the garage, the installer's invoice, or the warranty registration, and confirm the exact product line on the manufacturer's site.
More on hail ratings in impact-resistant shingles in Georgia and on shingle types in architectural vs 3-tab shingles.