The impact resistance rating system
The ANSI/FM 4473 standard tests shingles by dropping steel balls of increasing sizes onto samples and inspecting for cracking. The four classes are:
| Class | Test projectile | What it means |
|---|---|---|
| Class 1 | 1.25" steel ball | Basic — minimum resistance |
| Class 2 | 1.5" steel ball | Moderate resistance |
| Class 3 | 1.75" steel ball | Good resistance |
| Class 4 | 2.0" steel ball | Maximum resistance — no cracking |
A Class 4 shingle passes the 2-inch impact test with no cracking. The test simulates golf ball-sized hail (1.75") with margin — the same size that caused significant damage in Northeast Ohio during the April 2026 hailstorm.
Is Class 4 worth it in Northeast Ohio?
Northeast Ohio averages 3–5 significant hail events per year. Golf ball-sized hail (1.75") occurs during major storm systems — events that have historically caused widespread roof damage across Cuyahoga, Summit, and Lake counties. For a home that may experience multiple hail events over a 25–30 year roof lifespan, Class 4 shingles provide meaningful protection.
The economics also work. Class 4 shingles cost approximately $800–$1,500 more than standard architectural shingles on a typical Northeast Ohio home. Many insurance companies offer premium discounts of 20–30% for Class 4 installations — discounts that can pay back the upgrade cost within 5–8 years while providing protection for decades.
GAF Timberline UHDZ — Class 4 for Ohio homes
The GAF Timberline UHDZ is Atlas Roofing's Class 4 option. It uses dual-layer construction with a reinforced glass mat — the same dimensional appearance as the standard Timberline HDZ but with significantly higher impact resistance. It carries the same LayerLock technology, WindProven wind resistance, and StainGuard Plus algae resistance as the HDZ, plus Class 4 impact rating. Available in the same color range as the HDZ.
Ask your insurance company: Before choosing between standard and Class 4 shingles, call your insurance company and ask what discount they offer for Class 4 impact-resistant roofing at your address. The answer often makes the upgrade decision straightforward.