Where ice forms
De-icing targets specific spots where meltwater freezes again.
- The edge of a sloped roof. Water running under the snow freezes when it reaches the overhang, which is colder than the rest of the roof. The frozen water forms a ridge that holds water back behind it. That ridge is an ice dam.
- Gutters and downspouts. Once full of ice, they drain nothing and pull hard on their fasteners.
- The drain and scuppers of a flat roof. A single plug of ice is enough for meltwater to pool on the roof.
Why ice is not broken off
Ice bonds with whatever it covers. Hitting the ice means hitting the roof.
- A frozen shingle is brittle. It can split or come away with the chunk of ice.
- A flat roof membrane can be punctured by a pick, and the hole often stays invisible until the next thaw.
- A gutter loaded with ice can tear away from the wall.
What you do, and what you do not do
Never go up on the roof. Do not climb a ladder to break the ice, and do not hit icicles, even with a long handle.
What you can do from the ground or from inside:
- look at the roof from the ground or a window and photograph it
- keep everyone away from the base of walls where icicles hang
- protect the inside if water gets in by moving furniture and catching the water
- write to us through the form and describe what you see
When to have ice removed
Write to us in these situations. If water is coming in and you cannot wait for our reply, also look for a company that answers the phone.
- water is getting into the house, often at the ceiling near an outside wall
- a thick band of ice above the gutter keeps growing week after week
- large icicles hang over an entrance, a sidewalk or a parking spot
- water sits on a flat roof because the drain is caught in ice
The Régie du bâtiment du Québec (RBQ) calls roof snow removal a risky operation and considers it wise to hand it to a specialized company that knows the methods that avoid damaging the waterproof membrane.
How we work
De-icing is most often done with steam. Ask us which method we plan to use. Steam melts the ice without impact, exactly where it is aimed.
On an ice dam, we generally start by opening channels so the trapped water can drain. We then clear the roof edge and the gutters. Removing all the ice is not always useful. The goal is for water to find its way out and for nothing to threaten to fall.
What comes next
De-icing removes today's ice. Ice that comes back every winter at the edge of a sloped roof generally means the house is losing heat through the attic. That cause, linked to insulation and ventilation, is covered elsewhere on the site, in the pages on shingle roofs.
Frequently asked questions
How do you fix an ice dam on a roof?
In the short term, the fix is to have the ice removed with steam, and in the long term, to correct the heat escaping through the attic. Steam reopens the path for water without striking the roofing. As long as the roof stays warmer at the top than at the edge, the ice eventually comes back.
Does all the ice need to come off the roof?
Not necessarily. What matters is that water can drain and that no block of ice threatens to fall.
Does de-icing solve the problem for good?
No. De-icing deals with the emergency, meaning the trapped water and the ice that weighs on the roof or threatens to fall. If the cause is not corrected, the ice can return to the same spot after a few freeze-thaw cycles.
Official sources, consulted October 8, 2026: