How Much Weight can your roof support during a snow storm

1/27/2016 (Permalink)

Estimate How Much Weight Your Roof Can Support

• Unless the roof structure is damaged or decayed, most residential roofs, regardless of the location of the house, should be able to support 20 lb per square foot of snow before they become stressed.
• In some areas of New England and in mountainous areas throughout the United States, snow loads used in home design may be considerably higher and the roofs may be able to resist a greater depth of snow.
• If you live in an area known for lots of snow, you can probably check with your building department to find out if higher loads were used at the time your home was built.

Estimate How Much the Snow on Your Roof Weighs Using These Guidelines from IBHS

Fresh snow: 10–12 inches of new snow is equal to one inch of water, or about 5 lb per square foot of roof space, so you could have up to 4 feet of new snow before the roof will become stressed.

Packed snow: 3–5 inches of old snow is equal to one inch of water, or about 5 lb per square foot of roof space, so anything more than 2 feet of old snow could be too much for your roof to handle.

Total accumulated weight: 2 feet of old snow and 2 feet of new snow could weigh as much as 60 lb per square foot of roof space, which is beyond the typical snow load capacity of most roofs.

Ice: 1 inch of ice equals 1 foot of of fresh snow.

More Infromation: https://disastersafety.org/ibhs-risks-freezing-weather/prevent-roof-collapse-homes/