Why east-of-Ridge roofs need more nails, longer membrane, and tighter ridge caps.
The lake breeze and the lake-effect northeaster
Two different wind patterns shape Evanston's roofs. The summer lake breeze is a steady 10–20 mph easterly that does no damage by itself but accelerates UV exposure and the drying-out cycle of asphalt shingles. The fall and spring lake-effect northeaster — sustained 35–55 mph with gusts to 70 — is what tears shingles off east-facing slopes east of Ridge Avenue several times each decade.
Installation differences for high-wind zones
Six nails per shingle instead of the standard four. Synthetic underlayment with extended overlap. Hand-sealing of every starter and ridge cap regardless of weather. Drip edge installed under the underlayment at the eave and over the underlayment at the rake. Ridge cap installed with two nails per cap rather than one. Field nails set tight but not over-driven — over-driven nails cut the mat and create the failure point wind exploits.
Which homes need this
Everything east of Ridge Avenue. Everything within four blocks of Sheridan Road north of Davis. Any home on a bluff or with a long east-facing exposure. The far west side of Evanston, sheltered by the Mile of trees along Ridge, can use standard installation methods — but we still default to high-wind everywhere because the cost difference is negligible.
Why this matters for the warranty
GAF, CertainTeed, and Owens Corning all publish high-wind installation requirements. Roofs not installed to those requirements may have wind-damage claims denied by both the manufacturer and your homeowner's insurance. Standard installation is the cheapest way to a roof that fails its first big storm.