Roof Leak in Winter: What to Do First

Water coming through a ceiling in January is unsettling, and the instinct is to get on the roof and find it. Do not. Icy slopes are how people get badly hurt, and almost everything useful in the first hour happens inside the house.

First, limit the damage

• Move furniture and anything electrical out from under the drip, and get a container under it
• If the ceiling is bulging or sagging, there is water pooling above it. Spreading a drop sheet and putting a small hole at the low point with a screwdriver lets it drain in a controlled way instead of bringing the whole section down at once
• Turn off power to any light or outlet near the water at the breaker
• Take photographs and short videos as you go, before you clean anything up

Those photos matter more than people expect. If the damage ends up on an insurance claim, a record of the state it was in is worth having.

Then work out whether it is actually a leak

In a Calgary winter, a good share of what gets reported as a roof leak turns out to be something else, and the fix is different for each.

Attic condensation is the most common. Humid household air reaches the cold roof deck, freezes onto it, and then melts when a chinook arrives, dripping onto the insulation and through the ceiling. The signature is water appearing during or just after a warm spell, often in more than one spot, with frost visible on the underside of the sheathing when you look.

An ice dam backs meltwater up under the shingles at the eave. Water usually shows up at the top of an exterior wall or along the edge of the ceiling near the outside wall, and there is visible ice along that section of roof.

An actual breach in the roof, from lifted shingles, a cracked plumbing boot or failed flashing, tends to drip in the same spot regardless of what the weather is doing.

A frozen or split plumbing line is worth ruling out as well, particularly if the water is clean, constant and nowhere near an exterior wall.

Look in the attic, carefully

With a flashlight, look for the wet area on the underside of the sheathing and for the highest point of staining. Water runs along rafters and travels before it drops, so the wet patch on your ceiling is often well away from where it got in. Do not step between the joists, and do not go up if the space is packed with blown insulation you cannot see through.

What not to do

Do not go up on a snowy or icy roof. Do not chip at ice with anything metal, because you will damage shingles and probably the deck underneath. Do not run a heater in the attic to speed anything up.

When to call

Call the same day if water is actively running, if the ceiling is sagging, or if it is coming in near electrical. Anything slower can wait until morning, with a container under it and photos taken.

We offer free roofing inspections across Calgary and area.