A deformation with no way back
A curled shingle generally does not lie flat again, and the damage continues.
- The lifted edge gives the wind a grip, and the adhesive strip that held it comes loose.
- Once free, the shingle slaps with every gust. It wears along its row of nails until it breaks.
- In rain and wind, water gets under the lifted edges.
Curling is one of the shingle problems to have examined without delay, even when there is no leak.
Three shapes to recognize from the ground
From the yard, with binoculars, the shape of the deformation already guides the search.
- Cupped. The sides of the shingle turn up. Its exposed face has dried and shrunk more than its hidden face.
- Clawed. The middle rises while the edges point down. It is often seen on a shingle at the end of its life.
- Wave or line. The same bump lifts several shingles in a row. The shingle is often not to blame: it is the support that has moved.
Four possible origins
Time. The sun gradually drives the oils out of the asphalt, which stiffens and shrinks. On a roof nearing the end, the deformation spreads to every slope, starting with the south-facing one.
An overheated attic. Without enough air circulating, the attic overheats in summer and the shingles age faster. A roof deformed well before its time warrants our examining the soffits and vents.
Household moisture. Humid air rising from inside condenses under the deck. The wood swells and moves, and the panels lift at their joints, pushing the shingles. Straight ridges at regular intervals are the sign.
The installer's work. With too few nails, or nails in the wrong place, the shingle is free to twist. Underlayment installed wet or with wrinkles also creates ripples visible on the surface.
Changing a few shingles, or the whole roof
A handful of twisted shingles, grouped in one spot, can be replaced. There is one condition: the neighbouring shingles must bend without breaking. We lift them to insert the new pieces.
If the deformation is everywhere, repairing leads nowhere. The roof must be redone, and the cause fixed in the same job. New shingles installed over an attic that is still poorly ventilated or still humid will deform in turn.
You do not climb up to reseal a lifted shingle. Photograph the slope from the ground and show us the photos during the visit.
Frequently asked questions
My roof is curling but not leaking. Is it urgent?
The leak is not necessarily for tomorrow, but the risk is rising. Each lifted edge lets in wind-driven rain and tears off more easily. Request a visit before you see a stain on the ceiling.
Only one slope is deformed. What does that mean?
A single deformed slope is often the one that gets the most sun and ages before the others. The cause may also be specific to that slope, for example a bathroom fan exhausting its air into the attic right below, or soffits blocked on that side.
Is it acceptable for shingles to curl less than ten years after installation?
No. Four leads need checking: attic ventilation, moisture, the installation and the product itself. Find the contract and the warranty text, then ask the roofer who did the installation to come and see.