Class 4 Impact Resistance
The highest impact resistance rating under UL 2218 testing.
What the Rating Means
UL 2218 (also referenced as FM 4473) is a lab test that drops steel balls of increasing size onto a shingle sample to simulate hailstone impact. Class 4 is the highest rating on the scale — the shingle must show no cracking after impacts from a 2-inch steel ball, roughly equivalent to golf-ball-sized hail.
The Insurance Angle
Ohio doesn't mandate an impact-resistant discount statewide, but most major carriers writing policies in Fairfield, Hocking, and Perry counties offer a premium credit — commonly 10–35% off the roof/wind portion of your premium — for a documented Class 4 roof. The discount is usually permanent for the life of the roof, not just the first year, which can offset the material upgrade cost within 5–8 years depending on your policy.