How Much Snow On Roof Is Too Much

How much snow can my roof hold.

How much snow on roof is too much.

So how much snow does this equal. What precautions can i take to avoid too much snow on the roof. 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. The drifts on the roof were 5 feet deep.

As it turns out while this latest blast from old man winter did dump a lot of snow on us it s probably not too much for most residential structures here in southeast minnesota. 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. A depth of more than 30 cm of snow may be greater than your roof can support. How much snow is too much for a roof to handle.

Most roof designs can handle snow loads of 20 40 lbs per square foot. Two feet or more of old. Last winter we had snow on the ground that was up to our hips. This is based on the approximate measure of a cubic foot of snow having a mass of 10 pounds.

The chart below courtesy of paul schimnowski p e gives some examples of snow loads. For the twin cities metro area the roof snow load equals 35 pounds per square foot or 7 x 50. Six inches of wet snow is the same weight as 38 inches of dry snow. You have probably heard of or seen the difference between wet snow and fluffy snow.

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. 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. As everyone knows cold fluffy snow is very light while wet snow can be extremely heavy.

One of the major determining factors for how much snow is too much for your roof is how heavy the snow fall is. Packed snow however weighs more. Wet snow weighs considerably more than dry or fluffy snow because as you can probably guess water weighs more than air.