What do curling shingles mean?
By Best Roofing Answers · Published May 2026 · Updated July 2026
Curling shingles — edges lifting up (cupping) or centers rising (clawing) — usually indicate the shingle mat has lost its plasticizing oils and is past functional life, or that attic ventilation is inadequate; field-wide curling is a strong signal for full replacement, while isolated curls are sometimes repairable.
Why shingles curl
Per manufacturer product data (GAF, CertainTeed, Owens Corning), asphalt shingles rely on volatile oils to stay flexible. Sustained attic temperatures above ~150°F (usually a ventilation failure per IECC and IRC R806) drive those oils off years early, and the mat cups or claws once oils are gone.
Once curling covers more than roughly 30% of the field, NRCA guidance and the standard repair-vs-replace rule call for replacement; the seal strips can no longer engage and the roof is a wind-loss claim waiting to happen.
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