Impact Resistant Shingles Explained

UL 2218 Classes, Insurance Credits and When to Upgrade

Impact resistant shingles are products that have passed the UL 2218 steel ball test without cracking the mat, and Class 4 — a two inch ball dropped twice on the same spot — is the top rating in the series and the one insurers recognise. Most achieve it with polymer modified SBS asphalt that flexes and rebounds instead of fracturing, sometimes with a reinforcing scrim laminated to the back, which also makes them heavier per square and more forgiving in cold weather and under foot traffic. This guide explains all four impact classes and exactly what the test does not cover, how the construction differs from standard architectural shingles, and the three questions to ask your carrier before choosing a product: whether they credit a Class 4 roof, how much, and what documentation they need. It closes with a table of situations where the upgrade is a strong case and where standard architectural shingle is enough.