Roof leak repair means finding where water gets past the roof and fixing that spot: a lifted or broken shingle, failed flashing around a chimney or skylight, a cracked vent boot, or a worn valley. In Calgary, most leak repairs cost between $150 and $3,000, based on prices local roofing businesses publish. The hard part is finding the source, because water often travels along the decking or rafters before it shows on your ceiling.
This page covers what to do the moment you see a leak, the usual causes in Calgary, what repairs cost, and why some winter leaks have nothing to do with a hole in the roof. For other roof problems, see roof repair in Calgary.
What should I do when my roof starts leaking?
Protect the inside first, then call a roofer. Move furniture and electronics away, put a bucket under the drip, and soak up standing water. If water is pooling in a bulging ceiling, a small hole at the lowest point lets it drain into a bucket instead of bringing the ceiling down. Take photos for your insurer. Do not climb on a wet or icy roof.
If the water is near light fixtures or outlets, switch off that circuit at the panel. In a storm, a roofer may be able to put a tarp over the area as a temporary fix until the real repair can be done in dry weather.
If the leak came from storm or hail damage, the City of Calgary advises contacting your home insurance provider before any repair work.
Where do roof leaks usually come from?
Most roof leaks start at the places where the roof is interrupted: flashing around chimneys, skylights and where the roof meets a wall; rubber boots around plumbing vents; valleys where two slopes meet; and missing or damaged shingles. In Calgary, wind lifting shingle edges, hail breaking shingles and their seals, and ice dams at the eaves are common causes. A stain on the ceiling is rarely right below the source.
| Where the stain is | Likely source above |
|---|---|
| Near a chimney or skylight | Flashing that has pulled away or rusted |
| In a bathroom or near a plumbing stack | Cracked rubber vent boot |
| Along an outside wall, in winter | Ice dam at the eaves |
| Ceiling in the middle of a room | Damaged shingles or a worn valley higher up |
| Many small spots after a cold snap | Frost melting in the attic, not a hole |
Why does my roof leak only in winter?
Winter leaks in Calgary often come from ice dams or attic frost, not holes in the roof. An ice dam forms when heat from the house melts snow on the roof and the water refreezes at the cold eaves. Water then backs up under the shingles. Attic frost forms when warm, moist air leaks into a cold attic and freezes on the underside of the roof, then melts in a chinook and drips through the ceiling.
Both are fixed below the roof as much as on it: sealing air leaks from the house into the attic, adding insulation, and making sure the soffit and roof vents are clear. A roofer who only replaces shingles will not stop either one.
How much does it cost to fix a roof leak in Calgary?
Most roof leak repairs in Calgary cost $150 to $1,000 when the cause is simple, like a few shingles, a vent boot or a small flashing reseal. Larger flashing work, valley replacement or storm damage across a wider area runs $1,000 to $3,000. When the leak has rotted the decking or the framing, repairs can reach $3,000 to $5,000 or more. These ranges come from prices published by Calgary roofing businesses.
The cost climbs the longer a leak runs. Water that sits in insulation and wood for months turns a flashing repair into decking and drywall replacement. That is the strongest reason to fix a leak quickly, even a small one.
What makes a leak repair cost more:
- A steep or high roof that needs extra safety setup
- A leak source that is hard to find and needs testing
- Rotten decking under the shingles
- Shingles that no longer match and need a larger area replaced
Do metal roofs leak more than shingles?
No. A well-installed metal roof does not leak more than an asphalt shingle roof. Metal roof leaks usually come from fasteners whose rubber washers have worn out, from seams and flashing, or from poor installation, not from the metal panels themselves. Exposed-fastener metal roofs need the screws checked and replaced over the years. Standing seam metal roofs hide the fasteners and have fewer places for water to get in.
On any roof, the details decide whether it leaks: flashing, penetrations and the edges.
Questions people ask
How do you stop a leaking roof during heavy rain?
You stop the damage inside, not the leak itself, until the rain ends. Catch the water, move belongings, and drain any bulging ceiling into a bucket. If you can safely reach the attic, put a container under the drip and a board across the joists to stand on. Leave tarping the roof to a roofer: climbing a wet roof in a storm is dangerous.
What is the best way to fix a leaking roof?
The best way is to find the exact source and replace what failed: the broken shingle, the lifted flashing, the cracked vent boot. Caulk and spray sealants hide the problem for a while but rarely fix it. A good roofer traces the water path from the attic and from the roof, then shows you the cause before quoting the repair.
Is it expensive to fix a leaky roof?
Usually not, if you catch it early. Simple leak repairs in Calgary often cost a few hundred dollars, based on local roofing businesses' published prices. A leak left for months can cost thousands once it has damaged the decking, insulation and ceiling. Fixing it quickly is the cheapest option.
What happens if a roof leak is left untreated?
The water soaks insulation, rots the roof decking and rafters, stains and weakens ceilings, and can lead to mold. In winter it can freeze and widen the gap. What began as a small flashing repair can turn into replacing a section of roof and the drywall below it.
Will my home insurance cover a roof leak?
It depends on the cause and your policy. Many policies cover sudden damage, like hail or wind tearing shingles off, and often exclude leaks from wear and tear or poor maintenance. Call your insurer and ask, and get a roofer's report with photos of the cause. Your insurer decides what is covered.
Sources
- Ice dam (roof), Wikipedia
- City of Calgary, What to do about damage from storms
- Published repair prices of three Calgary roofing businesses, checked October 2026
Last updated