How Much Snow On Roof Is Too Much

The drifts on the roof were 5 feet deep.

How much snow on roof is too much. Most roof designs can handle snow loads of 20 40 lbs per square foot. Last winter we had snow on the ground that was up to our hips. Considering the snow type even more than the buildup depth is critical when assessing the state of the snow on your roof. But as the chart below shows packed snow with ice can easily overload a roof once it reaches about 12 off depth.

For the twin cities metro area the roof snow load equals 35 pounds per square foot or 7 x 50. One of the major determining factors for how much snow is too much for your roof is how heavy the snow fall is. This is based on the approximate measure of a cubic foot of snow having a mass of 10 pounds. What precautions can i take to avoid too much snow on the roof.

A depth of more than 30 cm of snow may be greater than your roof can support. You have probably heard of or seen the difference between wet snow and fluffy snow. Two feet or more of old. How much snow is too much for a roof to handle.

Packed snow however weighs more. According to this houselogic article it s not how much snow we got a foot at our place but the weight of the snow that we need to worry about. Building codes in your area require that roofs be built to withstand reasonable natural elements in your area so as long as your roof was. How much snow can my roof hold.

So how much snow does this equal. Six inches of wet snow is the same weight as 38 inches of dry snow. Ten inches of fresh snow equates to about five pounds per square foot which means your roof likely can support four feet of fresh snow. As everyone knows cold fluffy snow is very light while wet snow can be extremely heavy.

Wet snow weighs considerably more than dry or fluffy snow because as you can probably guess water weighs more than air. According to the national research council of canada a roof should be able to withstand pressure of at least 21 pounds per square foot psf this number can fluctuate based on regional building regulations but any well built roof should be able to sustain this much weight before it gets too stressed. The chart below courtesy of paul schimnowski p e gives some examples of snow loads.