How Much Is To Much Snow On My Roof

The municipal official that issues building permits can tell you what the design snow load is in your area.

How much is to much snow on my roof.

As everyone knows cold fluffy snow is very light while wet snow can be extremely heavy. The state s building code requires homes in the southern half of minnesota. In snow country that number might be anywhere from 30 or 35 pounds per square foot psf to more than 70 psf. Most roof designs can handle snow loads of 20 40 lbs per square foot.

The code says to see local conditions in these special zones. Our snow load calculator helps you to make the decision when to remove the snow from your roof by comparing the weight of snow with the load carrying capacity of the roof. Armed with that number a builder can frame the roof appropriately. But as the chart below shows packed snow with ice can easily overload a roof once it reaches about 12 off depth.

You can look for signs of an overloaded roof though. The chart below courtesy of paul schimnowski p e gives some examples of snow loads. How much snow is too much for a roof to handle. The building departments there say to use a 30 psf snow load.

How much snow a roof can hold depends on the type of snow roofline and material among other considerations. The 20 psf load is equivalent to 14 inches of snow at the design density while the 25 psf load is 17 inches. I wish there were a simple answer but none exists. There is a special zone in the northeast corner of the state where they get lake effect snow.

So how much snow does this equal.