The Institute of Business and Home Safety (IBHS) and the Underwriter’s Laboratory (UL) developed the UL 2218 classification to establish a national standard for roof impact resistance. Asphalt roofing shingles have ratings from Class 1 through 4 based on their resistance to a steel ball simulation test. A Class 4 roof shingle rating is the toughest.
Asphalt roofing shingles classified as impact resistant have a Class 4 rating designed to withstand high winds and hail damage. The shingle rating is not visible by merely looking at the asphalt shingles, although the impact rating is typically marked on the cellophane on the underside of the shingle.
Homeowners can expect to receive a 28% discount ($863 annual average savings) on their homeowners insurance policy with a Class 4 impact resistant roof.