Residential Roof Snow Loads

For example fresh snow is soft fluffy and light.

Residential roof snow loads.

Simple design check representative of worst case combined axial and transverse loading. Axial forces from snow loads and roof live loads should usually not be considered simultaneously with an extreme wind load because they are mutually exclusive on residential sloped roofs. 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. 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.

On the other hand snow that stayed on your roof for a few days will settle and while it seems that the cover gets thinner its weight doesn t change it s just the density that is different. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow. The 20 psf load is equivalent to 14 inches of snow at the design density while the 25 psf load is 17 inches. A great deal of confusion currently exists among engineers architects recreation specialists and maintenance personnel concerning the proper snow loading to use for the design and maintenance of trail bridges building roofs and other structures in mountainous high snow load areas.

The density of snow and hence its load per square foot depends on the type of snow. It calls for 20 psf throughout most of ohio and 25 psf along a north south strip in the eastern half of the state. The residential code of ohio which applies to one and two family homes shows a map indicating the required snow load.