Materials & Shingles · FAQ

What wind rating should an Illinois roof actually have?

Illinois IRC requires shingles rated for 90 mph design wind speed (which translates to a 60 mph actual gust under ASCE 7 conversion factors). Most architectural shingles sold today meet this with the standard 6-nail installation pattern.

Trill recommends going higher. The Mississippi-Missouri river corridor sees 70+ mph gusts in 2 to 3 storm events per year on average. A shingle rated for 110 mph (Class H under ASTM D7158) installed with a 6-nail pattern in high wind zones (gable ends, ridges, eave courses within 6 feet of any corner) holds up reliably through those events. The cost premium is minimal; the labor and material together add roughly $200 on a typical job.