Harsh Winter Weather And Roofs

It is that time again when Northern Virginia will be facing harsh winter conditions and dealing with snowstorms. The Institute for Business & Home Safety (IBHS) has provided guidance on how home owners can protect their home from harsh winter conditions, such as roof collapse due to heavy snow.

The IBHS Guidelines To Determine The Weight Of Snow Are:

• Fresh snow: 10-12 inches of new snow is equal to one inch of water, or about 5 lbs per square foot of roof space, so you could have up to 4 feet of new snow before you need to worry.
• Packed snow: 3-5 inches of old snow is equal to one inch of water, or about 5 lbs per square foot of roof space, so anything more than 2 feet of old snow could be dangerous.
• The total accumulated weight of two feet of old snow and two feet of new snow could be as high as 60 lbs per square foot of roof space, which is getting toward the design limits of even the best designed roof.
• If there’s ice, it’s much heavier, with one inch equaling about a foot of fresh snow.

The snow weight risk of a roof depends in large part on the age of the home. Older roofs can suffer from corrosion which can reduce the ability to resist high snow loads. In addition, homes with lightweight roofs, such as metal buildings, typically have less capacity to handle a high snow load. For flat roofs, the step-down area between roof sections presents a problem due to the tendency for ice and snow collection.

How Much Weight Can My Roof Handle?

According to IBHS, most roof designs can support at least 20 pounds per square foot. However, design loads can range from 10 pounds to 20 pounds per square foot in Mid-Atlantic states. Of course there are many factors to consider here such as the roof’s condition and age. You should always discuss with a Style Roofing professional whether or not your roof can handle a harsh winter storm.