Having a sloped roof cleared of snow

An order imposed on snow removal workers

The CNESST (Quebec's workplace health and safety board) ranks the work methods. Workers start with whatever keeps them on the ground.

1. From the ground. For a sloped residential roof, the CNESST considers that a long-handled tool used from the ground is very often enough.
2. From a lifting device fitted with guardrails. The worker stays inside the platform and wears a harness at all times. The device is not used to step onto the roof.
3. On the roof. The CNESST writes that this method must only be used as a last resort.

When you order roof snow removal for a sloped roof, ask us which of the three methods is planned, and why.

Before anyone climbs up

According to the CNESST, three findings must be made before a worker is sent onto the slope:

• the work cannot be done from the ground,
• it cannot be done with a lifting device,
• the remaining snow still poses a risk to the structure.

If all three conditions are met, the CNESST requires fall protection measures and suitable planning.

Why the slope is dangerous

The CNESST points out that grip is not guaranteed on a snowy or icy surface. It flags a special case: very smooth metal roofs encourage snow to break away suddenly.

This danger applies to you too. Under a loaded metal roof, do not walk along the wall and do not let children play there.

Where the snow falls

The CNESST asks that snow be removed from a safe position, outside the area where snow and ice fall. In its method for flat roofs, it also requires that this area be marked off on the ground and closed to access. Ask for the same precaution for your roof slopes. Before the day of the work, settle these points with us.

• Entrances. Which one stays usable during the work, and which one is closed.
• What is at the foot of the walls. Cars, a temporary shelter, bins, outdoor units. Have whatever can be moved moved, and point out the rest.
• The fallen snow. Who clears the doors and stairs afterward. The Régie du bâtiment du Québec (RBQ, Quebec's building authority) asks owners to keep exits and the path to the street clear.

Also point out power lines. Hydro-Québec asks that no person and no tool come within three metres of medium-voltage lines. It states that low-voltage lines, the ones that connect houses to the grid, are not free of danger: their insulating sheath can be cracked or damaged.

The roof covering and the bottom of the slope

The Régie recommends leaving a thin layer of snow on the roof. It notes that specialized companies know the methods that avoid damaging the waterproofing.

A digest from the National Research Council of Canada, published in 1968 and kept as a historical reference, observes that ice dams generally do not form when the eaves are free of snow. It lists removing snow from the eaves and valleys among the temporary measures, to be done with the proper precautions.

Frequently asked questions