Snow raises concerns about snow load concerns on roofs

Posted at 3:15 PM, Mar 01, 2019
and last updated 2019-03-01 18:11:21-05

Recent snows are causing vehicle slide-offs, avalanches, and school closures. The snow is also causing problems over our heads.

Snow is pretty heavy but it really depends on what kind of snow we’re seeing and that depends on the temperature and water content.

It’s called snow water ratio, which temperature plays a big role in determining. Higher temperatures mean heavier snow. Luckily recent temperatures in places like Bozeman and Butte have ranged from -10 to 10 degrees which means we’ve seen normal to fluffy snow. With 1 to 2 feet of snow being reported across most of the area, on a 1,500-square-foot home, that’s up to 18,720 lbs which is the equivalent to three pickup trucks.

Obviously, this adds a lot of stress to our rooftops, but engineers take into consideration criteria such as location, elevation, and 50-year climate data before construction.

“Once in every 50 years you might have a certain amount of snow on the ground and that’s what you want to design for so that your roof is likely through the 50-year design,” Assistant professor of Civil Engineering at MSU Chris Borstad said.

So most of SW Montana is safe from roof collapses.

“You would need about 4 feet or more of that kind of snow on roofs around here to reach the building code which is 40 lbs per square foot, so if your roof is built to code here in Bozeman, it would need to withstand 40 lbs per square foot of snow load on the roof,” Borstad added.

For a better idea of what your roof can handle, check out this website.

Reporting by Carson Vickroy for MTN News