When designing or engineering a home in our area, the snow load that a roof is designed for is taken from the County Building Department’s snow load information. Using this data for a home’s design is a part of the design requirements for a homebuilder to get a building permit in Central Oregon. However, even when using this required data to design a home’s roof it’s possible to have unusually severe winter weather that exceeds the historical data used to design the roof system. It’s a homeowner’s responsibility to monitor the snow load on their roof and take appropriate maintenance action when snow loads exceed the design requirements.
It’s not too hard to identify when a period where more snow than normal falls. Whether you turn on the news, read a newspaper, or simply look out the window you should be able to gauge if there is an excessive amount of snow on the ground. You can be sure there is as much snow on your roof as what’s on the ground, if not more. Additionally snow and prolonged freezing temperatures can lead to the formation of ice dams that can potentially end with water infiltration into the home resulting in water damage (see blog on ice dams).
Different types of roofs and roof materials are more susceptible to snow and ice dam damage than others. Generally the lower the pitch of your roof the more concerned you should be of potential water damage or roof failure.
If the snow load is excessive you should remove the snow in a way to avoid damage to the roofing. When a homeowner hires someone to do this maintenance work it’s best to hire a licensed and bonded roofer as they are not only set-up to safely work on roofs, but they should be the trade that does not damage the roofing. If ice damming is severe then the ice dam should be removed as well.