Answers · Is something wrong?
Why are my shingles curling?
The short answer
Curling at the edges is usually age and heat, often driven by poor attic ventilation cooking the shingles from below. Cupping in the middle more often means moisture, either from below or from a shingle laid over an uneven surface. Widespread curling means the roof is near the end; a patch of it means a local cause worth finding.
The two shapes
- Clawing or curling: the edges lift and the middle stays down. Heat and age, and frequently an attic that runs hot because it does not vent.
- Cupping: the middle rises and the edges stay down. Moisture, sometimes from below through an unventilated deck, sometimes from installation over a wavy or damp surface.
Where it is happening matters
Curling concentrated on one slope, usually the one with the strongest sun, is exposure. Curling concentrated above a particular room is often that room's exhaust fan discharging into the attic. Curling everywhere is the roof's age. Telling a roofer which of the three you are seeing narrows the conversation immediately.
Also asked
- Can curled shingles be flattened?
- No, not durably. The mat has deformed and sealing them down does not restore the seal strip or the flexibility. Individual curled shingles near a detail can be replaced; a slope of them is telling you about the roof.
General information about roofs and about hiring, not advice about your building. Roofing contractor licensing, permits, insurance practice and deductible rules are set state by state and province by province across the United States and Canada, so your own authority is the current answer.