In Edmonton, a winter roof leak almost always comes from one of three things: an ice dam pushing meltwater under your shingles, attic rain (frost inside the attic melting during a warm spell), or a true roof leak through damaged flashing, vents or shingles. They look the same from inside your house, a stain or drip on the ceiling, but each one has a different cause and a different fix.
Getting the cause right matters. Homeowners often pay for a roof repair when the real problem is attic moisture, or seal an attic when the real problem is a cracked vent boot. Either way, the leak comes back next winter.
This guide shows you how to tell the three apart in a few minutes, what to do in the first hour, and what a winter roof leak repair in Edmonton usually involves.
Ice dam, attic rain or roof leak? How to tell in 5 minutes
Match what you see to the most likely cause. Timing and location of the water are your best clues.
| What you notice | Most likely cause | Why |
|---|---|---|
| Water near exterior walls or above windows, thick ice along the eaves, icicles | Ice dam | Meltwater backs up behind ice at the roof edge and runs under shingles |
| Drips in many spots on the top-floor ceiling, starting on the first mild day after a cold snap | Attic rain | Frost built up on the underside of the roof deck melts all at once |
| Wet spots around bathroom fans or light fixtures, frost or ice on nails in the attic | Attic rain | Warm, moist air is escaping into the attic and freezing |
| Leak in the same spot every time, near a chimney, skylight or plumbing vent | Roof leak (flashing or vent) | Water gets in through a failed seal, usually during melts or rain |
| Leak started after a summer storm or high winds, stain grows during thaws | Roof leak (storm damage) | Lifted, cracked or hail-bruised shingles let water through |
| Fog or water on a skylight or sun tunnel, no stain around it | Condensation | Indoor humidity is collecting on cold glass, not a roof leak |
Quick test: if the drips appear in several places at once on a sunny, mild day after a long cold spell, think attic rain first. If water shows up in one spot every time snow melts, think flashing or vents. If you can see a ridge of ice along the eaves, think ice dam.
Cause 1: Ice dams
An ice dam is a ridge of ice along the edge of your roof that traps meltwater behind it. Heat escaping from your house warms the upper roof, snow melts, the water runs down to the cold eaves and refreezes. The trapped water then works its way under the shingles and into your walls or ceiling.
Edmonton’s winters are made for ice dams, because temperatures often swing above and below freezing within a few days.
Signs it’s an ice dam:
- A thick band of ice along the roof edge and heavy icicles
- Water stains on exterior walls, around window tops or in closets on outside walls
- Leaks that start during a thaw, not during a cold snap
What to do: don’t chip at the ice with a hammer or shovel; you’ll tear the shingles and eavestroughs. A roofer can remove the dam safely with steam. The long-term fix is stopping heat loss into the attic and making sure your eavestroughs drain. Our full ice dam prevention and repair guide covers this step by step.
Cause 2: Attic rain — the “leak” that isn’t your roof
Attic rain happens when frost builds up inside your attic during a long cold snap, then melts all at once when the weather warms up. The water drips through the insulation and stains your ceiling, so it looks exactly like a roof leak. But the water came from inside your house, not through the shingles.
Here’s how it builds up. Everyday moisture from showers, cooking and laundry rises as warm air. If that air leaks into the attic through gaps around the attic hatch, pot lights, bathroom fans or plumbing stacks, it hits the cold underside of the roof deck and freezes. After a week of -25°C weather, an attic can be coated in frost. The first mild, sunny day melts it faster than the attic can dry out.
Signs it’s attic rain:
- Drips or stains in several places on the top-floor ceiling at once
- It starts on a warm day right after a deep cold spell
- Frost or ice on roofing nails and the underside of the sheathing when you look in the attic
- Water around bathroom fans, light fixtures or the attic hatch
- Brown stains on the soffit from outside
What to do:
- Check your indoor humidity. In an Edmonton winter, most homes should stay around 30–35% or lower during cold snaps; a cheap hygrometer will tell you.
- Run bathroom fans during and after showers, and use your range hood when cooking.
- Make sure bathroom and kitchen fans actually vent outside, not into the attic. Disconnected fan ducts are one of the most common causes we find.
- Seal air leaks around the attic hatch, pot lights and plumbing stacks.
- Have a roofer check that your attic has enough intake and exhaust ventilation. Our roof ventilation guide explains how it should work.
Attic rain won’t be fixed by new shingles. That’s why diagnosis comes before any repair quote. Ventilation helps, but on its own it rarely solves the problem if humidity and air leaks aren’t dealt with too.
Cause 3: A real roof leak
A true roof leak means water is getting through the roof itself, usually at flashing, vent boots or damaged shingles. In winter these leaks show up mostly during melts, when snow on the roof turns to water and finds the weak spot.
The most common sources on Edmonton homes:
- Chimney and wall flashing. Old caulk cracks in the cold, and lifted flashing lets meltwater behind it. A proper roof flashing repair fixes the cause instead of adding more caulk.
- Plumbing vent boots. The rubber collar around vent pipes splits after years of UV and freezing.
- Skylights. Failed seals and snow drifting against the frame.
- Storm-damaged shingles. Edmonton’s wet, windy 2026 summer left many roofs with lifted or bruised shingles that didn’t leak until the first freeze-thaw. If your roof went through this year’s storms without an inspection, read our hail damage roof guide.
- Valleys. Where two roof slopes meet, snow and ice pile up and water runs heaviest.
Signs it’s a roof leak: the leak shows up in the same spot each time, sits below a chimney, vent or skylight, and gets worse during thaws or winter rain. Many of these are covered in our list of warning signs your shingles need repair.
What to do in the first hour of a winter roof leak
Whatever the cause, these steps limit the damage until a roofer arrives:
- Catch the water. Put buckets or towels under every drip and move furniture and electronics away.
- Relieve a bulging ceiling. If drywall is sagging with water, poke a small hole at the lowest point over a bucket. It’s better to drain it than let the ceiling collapse.
- Turn off power to wet light fixtures at the breaker if water is near them.
- Take photos and video of the stains, drips and any ice on the roof edge. You’ll need them for insurance.
- Look in the attic if it’s safe. Frost or ice on the nails and sheathing points to attic rain. Wet insulation in one spot points to a roof leak.
- Call for help. For active leaks, book emergency roof repair in Edmonton.
What not to do:
- Don’t climb onto an icy roof or shovel it yourself. A fall from a roof can be life-changing, and a roofer has the right safety gear.
- Don’t chip ice dams with tools or use salt on shingles.
- Don’t leave the attic hatch open to “dry it out”; that pushes more warm, moist air into the attic and makes frost worse.
- Don’t just caulk the spot you think is leaking. Find the cause first.
Can a roof be repaired in an Edmonton winter?
Yes. Leaks can and should be fixed in winter, but some repairs are temporary until warmer weather. Roofers can remove snow and ice, replace vent boots, re-secure flashing and install cold-weather sealants or temporary membranes. Some materials, like shingle sealant strips and torch-on membranes, bond best above certain temperatures, so a permanent fix may be scheduled for a milder day.
Typical winter costs in Edmonton (approximate, 2026):
| Winter repair | Typical cost (CAD) |
|---|---|
| Emergency tarp or temporary seal | $350 – $900 |
| Ice dam steam removal | $500 – $1,500 |
| Vent boot or small flashing repair | $200 – $800 |
| Leak repair with decking damage | $1,000 – $2,500 |
| Attic ventilation improvements | $300 – $1,500 |
After-hours and storm-day calls usually cost more. See our full roof repair cost guide for every repair type. If your roof is near the end of its life, our guide to replacing a roof in winter explains when that makes sense.
Pre-winter checklist: stop leaks before the first deep freeze
The best time to prevent a winter roof leak in Edmonton is October and early November, before snow sits on the roof for months. Work through this list now:
- Clean out eavestroughs and downspouts so meltwater can drain. Sagging runs need eavestrough repair before winter.
- Look for missing, lifted or cracked shingles from the ground.
- Check flashing around the chimney, skylights and walls for gaps or old caulk.
- Check plumbing vent boots for cracks.
- Look in the attic: insulation should be even, vents shouldn’t be blocked, and fan ducts should connect to the outside.
- Add weatherstripping to the attic hatch.
- Buy a hygrometer and keep indoor humidity in check through the cold months.
- Book a professional inspection if your roof went through this summer’s storms or is over 15 years old.
For the full seasonal routine, see our roof maintenance schedule and winter roof preparation guide.
Not sure what’s causing your leak?
Silverline Roofing finds the real source first, whether it’s an ice dam, attic moisture or a failed seal, and shows you photos before recommending any work. We serve Edmonton, St. Albert, Sherwood Park, Spruce Grove and Leduc.
Book a roof inspection before winter or contact our team for a leak repair.
Winter roof leak FAQs
Why does my roof only leak in winter?
Leaks that only appear in winter are usually caused by ice dams or attic rain, not a hole in the roof. Both happen when snow or frost melts and the water can’t drain away normally.
What is attic rain?
Attic rain is frost that builds up inside the attic during a cold snap and melts when temperatures rise. It’s caused by warm, moist indoor air leaking into the attic, and it often looks like a roof leak on the ceiling.
How do I know if it’s an ice dam or a roof leak?
Ice dam leaks usually appear near exterior walls and windows, with thick ice along the eaves. Roof leaks usually appear in the same spot each time, often under a chimney, vent or skylight.
Can roofers fix a leak in winter in Edmonton?
Yes. Roofers can remove snow and ice, replace vent boots and re-secure flashing in winter. Some permanent repairs may wait for a milder day if the materials need warmer temperatures to seal.
Should I remove snow from my roof to stop leaks?
Not by climbing up yourself. Clearing the bottom few feet of snow from the ground with a roof rake can reduce ice dams on low roofs; anything more should be done by a professional.
Does home insurance cover winter roof leaks?
Insurance usually covers sudden damage, but often not leaks caused by poor maintenance, ventilation or long-term attic moisture. Check your policy and take photos as soon as you notice the leak.
What humidity should my house be in winter to prevent attic rain?
Most Edmonton homes should stay around 30–35% or lower during cold snaps. If windows are frosting on the inside, humidity is likely too high.