Weight Of Snow On Pitched Roof
Expressing this in ratio form our sample roof has a 3 12 pitch.
Weight of snow on pitched roof. On average two feet of snow can equal up to 19 tons of weight on your roof which can significantly weaken the structure. So a risky roof is flat or slightly pitched and in a location that is exposed to the wind. This includes the ground snow load for your area terrain exposure roof type pitch and run. You can enter this value either as a ratio x 12 or as an angle whichever suits you better.
If you live in the us our snow load calculator compares the total weight on your roof with the permissible load calculated according to the standards issued by the american society of civil engineers regarding the minimum design loads for buildings and other structures asce7 16. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow. Rain sleet and ice add to the. Go to a snow load calculator and enter the information requested.
In addition the slope of the roof helps to dump some of that snow back on the ground removing more stress. You may need to create a new login account to use the new calculator. S 5 has updated the snow retention calculator to incorporate many new features including side by side comparisons for colorgard dualgard x gard 1 0 and x gard 2 0. To figure out the load on your roof take the depth of snow in feet and multiply it by the weight of a cubic foot of snow.
Fresh light and fluffy snow will weight much less than the dense packed or wet variety. Shallow roofs adjacent to or below taller steeper ones are especially vulnerable to a load of snow. Calculating the weight of snow is useful when you need to know the total weight it adds for example to calculate the weight on a roof. A steep roof does a much better job of handling snow than a flat roof does.
The roof pitch affects weight distribution allowing it to hold a little more snowpack safely. Consider removing accumulated snow from your roof to avoid collapse. Intuitively this is the number of inches of snow on your roof in the place where the cover is the thickest. S 1 25 p where s is the number of inches of snow on your roof and p is the pounds per square foot of that snow.
If your roof is pitched enter the length and width of the flat area covered by the roof. This will give you the kilogram per square metre psf or pounds per square foot snow load for your 3 12 pitch roof. If the snow weighs 10 pounds per cubic foot and there are 1 5 feet on the roof each square foot of the roof is getting 15 pounds of pressure.