Ice Dams and Heavy Roof Snow: When to Call a Pro
An ice dam is a ridge of ice that forms at the edge of the roof. Heat from the house melts snow higher up, the water runs down to the cold eaves and freezes again. Behind the dam, water pools and backs up under the shingles, then drips into the attic, walls and ceilings.
Warning signs
- Thick icicles along the gutters, especially over the front door or walkway.
- A band of ice along the roof edge while the rest of the roof is still white.
- Water stains or peeling paint on ceilings near outside walls.
- Gutters pulling away from the house under the weight of ice.
When roof snow is too much
Fresh snow is light, but wet or packed snow can weigh several times more. Flat roofs, garages, sheds and older homes are the first to suffer. If doors start to stick or you hear creaking after a storm, have the snow removed.
How we remove it
- Roof raking pulls snow off the lower few metres of a sloped roof from the ground or a ladder, without touching the shingles.
- Hand clearing on flat roofs with plastic shovels, leaving a thin layer to protect the membrane.
- Channels through the ice dam so trapped water can drain, plus removal of dangerous icicles.
Never chip at an ice dam with an axe or a hammer: it breaks shingles and gutters. And please do not climb onto an icy roof yourself.
Preventing ice dams next year
Most ice dams start with poor attic insulation or ventilation, and clogged gutters make them worse. Clean gutters in the fall and keep the lower edge of the roof clear after big storms.
More guides: Get your driveway ready for winter · Rock salt or ice melt? · Sidewalk snow rules in the GTA