Two roofs, two behaviours
In Montreal, a roof with a slope under 2:12 is considered a flat or low-slope roof. From 2:12 up, it is a sloped roof.
On a flat roof, snow stays where it falls until it melts. On a sloped roof, snow can slide toward the edges. The markers for deciding when to clear a roof are the same in both cases, but you look in different places.
On a flat roof
Where snow builds up. Parapets hold snow in like the sides of a tub. Wind pushes it against the neighbour's wall when that wall is taller.
What to watch. The drain comes first. A buried or frozen drain no longer lets water out, and winter rain then adds to the weight of the snow.
How we clear it. We locate the drain, vents and skylights before shovelling. We work with plastic shovels, leave a thin layer of snow on the membrane and clear around the drain. The snow goes down into the yard once the area below is closed off.
On a sloped roof
Where snow builds up. Snow piles up in the valleys, where two slopes meet. It also gathers at the bottom of the slopes, where ice forms.
What to watch. The edges need the most attention. Sliding snow lands on the entrance, the balcony or the car. Ice at the roof edge and icicles are a danger to pedestrians and cars, the Régie du bâtiment du Québec (RBQ) points out.
How we clear it. We lighten both slopes evenly, without scraping the shingles or their granules.
On a bungalow, the bottom of the roof is sometimes within reach from the ground. That is where the only method the RBQ describes for owners comes in. A roof rake with a telescopic handle lets you work from the ground and avoid any risk of falling. Stay well away from power lines, and never stand under the snow you are pulling.
Carports, balconies, sheds and garages
The RBQ calls for caution with temporary carports and reminds owners to clear emergency exits, balconies, sheds and garages too.
- Temporary carports. Clear them from the outside, without standing under them when they are loaded.
- Balconies. They sometimes also catch snow falling from a sloped roof.
- Emergency exits. A rear staircase blocked by snow is useless.
- Sheds and garages. Their roofs are often low and sit right under the snow sliding off the main roof.
List these surfaces in your quote request.
Frequently asked questions
Does a flat roof need clearing more often than a sloped roof?
Not necessarily. A flat roof keeps its snow longer, but no rule sets a frequency. In both cases, signs of overload and the weather decide.
Should the drain on a flat roof be cleared in winter?
Yes, when the drain is buried or frozen and rain or a thaw is on the way. That work is done on the roof and is our job. Do not go up to do it.
Can I use a roof rake on my flat roof?
No. A plex roof is out of reach from the ground and hidden behind parapets, and nobody should go up there. A telescopic roof rake is for the bottom of a sloped roof you can reach from the ground. For a flat roof, write to us through the form.
Official sources, consulted October 8, 2026: