Winter · December–February

Winter home maintenance for Canadian houses

A house covered in deep snow during winter

A house under heavy snow. Photo via Wikimedia Commons.

Winter maintenance is mostly monitoring rather than projects. The house has been sealed and the furnace serviced in fall; the goal now is to catch problems while they are small. Across most of Canada the recurring risks are the same: frozen pipes, ice dams at the roof edge, blocked exhaust vents under drifting snow, and excess indoor humidity that condenses on cold glass.

Keep water lines from freezing

Pipes freeze where cold air reaches them: exterior walls, unheated basements, crawl spaces, and the line to a hose bib. During a deep cold snap, keep cabinet doors open under sinks on exterior walls so warm air circulates, and let a faucet run a thin stream on the most exposed line. If you leave for several days, do not set the thermostat below a level that keeps interior walls above freezing.

Limit ice dams at the roof edge

Ice dams form when heat escaping into the attic melts snow on the upper roof, which then refreezes at the cold eaves and backs water up under the shingles. The durable fixes are an air-sealed, well-insulated attic and good ventilation, all best handled before winter. During the season, safely removing snow from the lower edge of the roof with a roof rake from the ground reduces the meltwater available to refreeze.

Do not climb onto a snow-covered or icy roof. Work from the ground with a roof rake, and never use open flame or an electric heat source to melt ice on a roof.

Keep exhaust and intake vents clear

High-efficiency furnaces, water heaters, and dryers often vent through a side wall close to grade. Drifting snow can block these vents, which is a carbon-monoxide hazard. After each significant snowfall, check that wall vents, the meter, and any fresh-air intake are clear. This is the winter task most often forgotten.

  1. Clear snow from furnace and water-heater exhaust and intake terminals.
  2. Keep dryer vents and the gas meter free of drifts and ice.
  3. Confirm carbon-monoxide detectors are working, especially near sleeping areas.

Manage indoor humidity

A tightly sealed winter house traps moisture from cooking, showers, and breathing. When that moist air meets cold window glass it condenses, and persistent condensation can lead to mould around frames. Use bathroom and kitchen exhaust fans, and lower humidifier output as outdoor temperatures fall, since the colder it is outside, the lower the indoor humidity that windows can tolerate without sweating.

RiskRoutine check
Frozen pipesDuring each hard cold snap
Ice damsAfter heavy snow on the roof
Blocked ventsAfter every snowfall
Window condensationOngoing; adjust humidity

Looking ahead to the thaw

Many winter problems only reveal their damage in spring. When the snow goes, follow the spring maintenance checklist to inspect the roof and foundation, and review the fall checklist to plan next year's preparation. General weather information for planning is published by the Government of Canada.