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Impact resistant asphalt shingles have become a familiar option for Minnesota homeowners rebuilding or replacing a roof after hail damage, largely because many insurance carriers offer premium discounts for their installation and because the products themselves are engineered to reduce the likelihood of future hail related claims. These shingles typically incorporate a modified asphalt formulation, sometimes with a rubberized or polymer additive, along with a reinforced fiberglass mat designed to resist fracturing under impact in a way that standard shingles are not specifically engineered to do. The additional material and manufacturing process generally place these products at a higher price point than standard three tab or architectural shingles, a cost difference that is relevant when a claim involves upgrading from a standard product to an impact resistant one.
The primary testing standard referenced in the industry is Underwriters Laboratories 2218, which rates shingle impact resistance on a scale from Class 1 to Class 4, with Class 4 representing the highest demonstrated resistance in the standardized test. The UL 2218 test involves dropping a steel ball of a specified size and weight onto the shingle from a set height and evaluating whether the impact fractures the shingle’s reinforcing mat, which is checked by examining the underside of the shingle for cracking after impact. A related test method, FM 4473 maintained by FM Approvals, uses actual ice balls rather than steel balls and is also referenced by some manufacturers and testing bodies as an alternative or complementary standard.
It is worth understanding that a Class 4 impact rating does not mean a shingle is immune to hail damage. It means the shingle demonstrated resistance to fracturing under the specific test conditions used, which involve a controlled impact energy that may be exceeded by sufficiently large hail in an actual storm. Minnesota experiences hail events across a wide range of stone sizes, and very large hail, sometimes exceeding golf ball or baseball size in isolated storms, can damage even a Class 4 shingle. Evaluating a claim involving impact resistant shingles still requires the same careful inspection for granule displacement, mat fracturing, and bruising that applies to standard shingles, rather than an assumption that the product cannot be damaged.
Insurance discounts for impact resistant roofing vary by carrier and by state, and whether a given policy includes such a discount, and how that discount interacts with a claim, is a coverage and underwriting matter that belongs to the policy and the parties rather than to the physical evaluation of damage. From a technical standpoint, an appraiser’s role remains focused on what damage exists and what it costs to address, independent of any discount program associated with the product.
Manufacturers publish product specific test certifications, and verifying that an installed shingle actually carries the claimed impact rating, rather than assuming based on general product category, is a useful step when the specific rating is relevant to a claim, since not every shingle marketed as impact resistant carries the same tested classification. Product identification codes printed on the shingle wrapper, when available from the original installation, offer the most reliable way to confirm exactly which tested product is on the roof.
This article is general education about how the appraisal process commonly works. It is not legal advice, and specific procedures can vary by state and policy.
Russ Lis is a working property insurance appraiser and umpire based in Minnesota, serving clients nationwide. Contact Appraisal Resolution.