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Are you worrying about your roof?
By Ian Cobb/e-KNOW
Record snowfall continues to pile up on East Kootenay roofs and more and more homeowners are starting to worry about the weight of the snow and the potential for collapses.
The National Research Council of Canada (NRCC) notes there are some quick signs you can look and listen for to give you a clue if the roof of your home is experiencing weight stress.
These signs can include unusual sounds from the roof or supporting walls, visible movement of walls or sagging of ceiling and cracking of drywall or plaster. Other signs may include doors that jam or water leaks that show up after a big snowfall.
“The configuration of your roof could be a factor. Pay special attention to areas on your roof where local snow accumulation occurs on a portion of a roof. For example, near dormers, valleys or on shed roofs. Roofs with a low slope or roofs covered with rough roofing material tend to accumulate more snow than steeper pitches or slippery roof finishes,” says the NRCC.
As for how much snow a roof can hold, there is no quick, easy answer, because it isn’t the depth of the snow but the weight that matters.
“The weight of snow can differ quite a bit; for example, compare lifting a heaping shovel of deep fluffy snow with a half-empty shovel of slushy snow.
An article in Popular Mechanics (February 2012) notes that roofs most at risk are flat or slightly pitched, and in a location that is exposed to the wind.
“Shallow roofs adjacent to or below taller, steeper ones are especially vulnerable to a load of snow sliding down from above. For example, low-sloping roofs over porches, carports, and hastily built additions (which also often have undersize rafters) can be vulnerable when the snow flies,” the article said.
Another hidden danger, according to Jeff Geary, a Popular Mechanics Homeowners Clinic contributor and an architect in Staten Island, N.Y., is a roof assembly from which collar ties have been removed.
Located about one-third of the way down from the ridge, the supports connect the rafters and counter the spreading effect created by snow loads.
“Many times I go into attics and find that homeowners have removed collar ties to get extra headroom, install a bedroom for the kids, or store holiday decorations,” Geary says. “Homeowners should know that collar ties are there for a reason.”
Regardless of your roof’s condition, remove drifts using a roof rake with an extension pole, or hire a pro for the job. Take care not to damage flashing or shingles; the goal isn’t to clear every flake, but rather to ease the load.
The NRCC concludes the best way to assess the snow on your roof and to answer all your questions is an on-site visit by a local expert. These are typically architects or consulting engineers. In some cases home inspectors also have this expertise.
