MONTREAL - Montrealers are distinguished for their snow removal skills as proven in their recent efforts to clear walkways and sidewalks following the massive Boxing Day snowstorm.

But when it comes to roofs many are perplexed and oblivious.

Heavy snowfalls can threaten a roof with collapse and can also have other effects on a home, according to an expect.

“Everything's forcing, your walls your foundation, everything, everything takes a beating,” said Jean-Marc Laplante of Docteur Calfeutrage. “The concerns are ventilations clogging up, the roof can collapse, ice build up.”

The latest warm spell may increase the burden because instead of drying out and blowing away, snow will instead melt and refreeze, becoming denser and less likely to evaporate.

“What happens is the snow becomes three times its weight, so it becomes very heavy for the structure of the home or building to support,” said Laplante.

"If you see cracks that have appeared in the past couple of days that weren't there before, that could be a clue that your roof has too much weight."

CAA Quebec does not consider roof collapse a serious risk for most residents but flat roofs are, they concede, a little more vulnerable.

They advise homeowners to examine for swelling on ceilings, doors not closing and other such signs of pressure from the top.

Quebec has seen several roof collapses in the past, perhaps the best known being that of the Olympic Stadium in 1999.

The most recent fatal collapse happened at the Gourmet du Village in Morin Heights which killed three women in 2008.


This article has been updated.