Why Are My Roof Shingles Curling, and Does It Mean a New Roof?

Older Victoria homeowners still call asphalt shingles 'duroid', and 'my old duroid is curling and cracking' is a phrase every local roofer hears. The curling roofs of the region are concentrated where whole neighbourhoods were built in one push: 1980s and 90s Broadmead, Dean Park and Brentwood Bay are hitting the end of their second roof together, while the first builder-grade roofs on 2000s Langford and Bear Mountain homes are starting to lift at the edges on sunny south slopes.

Ventilation is the local twist. Many 1960s and 70s Gordon Head and Royal Oak ranchers were built with minimal soffit venting and later stuffed with insulation that blocked what there was, so the attic runs hot in a July heat wave and damp all winter. Shingles cooked from below and soaked from above age faster than the product's rating suggests, which is why a roofer looking at curling will usually ask to see the attic before quoting.

An asphalt shingle is a fibreglass mat coated in asphalt and topped with granules. As the asphalt loses its oils to heat and UV it shrinks and stiffens, and the shingle can no longer lie flat. Edges that turn up are usually called curling; centres that sink so the corners rise are called cupping or clawing. Both are physical signs that the shingle has become brittle, which is why the Asphalt Roofing Manufacturers Association lists ventilation, heat and moisture among the main service-life factors.

Curling is a condition, not a leak. What it does is remove the roof's margin: a curled edge is a handle for the wind, and a brittle shingle cannot be lifted for a repair without cracking.

Most curling in Greater Victoria is simple age, but the inspection is worth doing because two of the causes change what the next roof should include.

• End of service life: local asphalt roofs last about 15 to 22 years by Shoreline Roofing's 2026 estimate, less on hot exposed slopes.
• Inadequate attic ventilation: without balanced soffit intake and ridge or roof exhaust, the attic bakes the shingles from below.
• Moisture in the mat: chronic damp from moss, shade or attic condensation.
• Two or more layers: a second roof laid over the first traps heat and hides the deck; tear-off of the extra layer adds $0.75 to $1.25 per sq ft in our pricing model.

Curling alone can usually wait for a scheduled inspection rather than an emergency call. The practical steps are to note how much of the roof is affected (one slope or all of it), find out the roof's age from your purchase documents or the previous owner, and count layers by looking at the edge of the roof at the eave or having the roofer check. Check ceilings and the attic after the next storm, because curled shingles are where wind damage starts.

Do not try to glue or nail curled edges down yourself. Working from a ladder on a brittle roof cracks shingles and adds a fall risk, and sealant-only fixes tend to fail within a season.

If the curling is widespread and the roof is past 15 years, most roofers will steer you toward replacement rather than repair, because there is no repair for brittleness. The question is timing: a roof with curling but no leaks can often be scheduled for the following dry season rather than done in a January panic, which also gives you time to gather two or three quotes and to fix the attic ventilation as part of the job. Use the calculator to see your own home's range, and the repair-or-replace tool if a roofer has suggested patching.