Canadian winters can be brutal. Canada has its share of snow and this can be a particular problem for house roofs. Snow can slide or fall from a roof and cause damage to people or property below. It can block exits and cause damage to gutters and other parts of the home.
All problems caused by heavy snows cannot be totally eliminated, but they definitely can be minimized.
One issue is that neither America or Canada have codes in place regarding snow retention for roofs. Therefore, it is important for building professionals to consider all aspects of the problem when designing a roof for snowy areas.
Although all materials have problems associated with them, metal roofs seem to perform best. They are the most durable, they can easily shed snow, and they rarely leak. With proper care, a metal roof can outlast other types of materials. One thing that is important is to make the roof extend out enough so that falling snow will not block access to the house and will provide a safe path to walk around the house.
A simple gable is the best design. Complicated gables and multi-level roofs tend to collect pine straw and snow in nooks and crannies while a simple gable will shed snow much better.
If you are building a home, it is best to remember that each hole in the roof provides a potential for a leak. This includes chimneys, skylights, and gables. Of course, you should build your home to suit your desires, but you should just keep this in mind.
Structures in snowy locations are usually built with a high pitch to the roof. This simply means that the roof is steep. Snow slides off a steeper roof more easily. Pitch is the ratio of vertical height (rise) to the horizontal span (run). Generally, a roof pitch of greater than 6.12 will shed snow effectively. This means that the roof rises six inches for every twelve inches of horizontal span.
A dark colored material is good, as it retains heat better than a lighter color.
Reducing heat loss from the roof will help to prevent ice dams and minimize damage to the roof. So, installing insulation with a value of R-50 or higher will decrease heat loss at the top of the roof. This equalizes the temperature of the roof and the outside temperature.
Also, venting below the roof deck helps to equalize the roof temperature so that snow will not melt and refreeze at the eaves.
