Install Impact Resistant Roof Coverings Having a Class 4 Rating When Tested to UL 2218 or FM 4473.

Most manufacturers have a line of shingles that have been tested to withstand significant hail events. The test standards typically cited are UL 2218 and/or FM 4473. UL 2218 is primarily intended for flexible roof covering materials while FM 4473 tests the impact resistance of rigid materials such as wood shakes, slate, and metal roofing. There are four classes of impact resistance with Class 4 having the highest performance. Recent IBHS research has shown that the most durable and hail resistant Class 4 asphalt shingles are those made using polymer modified asphalt. In some states such as Texas, insurance premium discounts are available for roof coverings meeting this standard, which helps make these products more cost-effective. This category of roof covering material is also usually more wind-resistant as well.