Class 4 is the highest rating under UL 2218 — the standard for impact resistance of roofing materials. Testing involves dropping a 2-inch steel ball from 20 feet onto the sample; Class 4 means no cracking or splitting. In Utah, Class 4 matters because the Wasatch Front sits in a recognized high-hail corridor. Class 4 roofing substantially reduces hail damage probability, qualifies for 15–30% insurance premium discounts with most Utah carriers, and extends the functional roof life between replacements. RainFire Builders specifies Class 4 as the standard recommendation — not a premium upgrade — for every Wasatch Front residential roof replacement.