Residential Roof Snow Loads

Snow loads roof snow loads are influenced by elevation general weather and moisture patterns slope direction exposure roof configuration and wind direction and severity.

Residential roof snow loads.

The 20 psf load is equivalent to 14 inches of snow at the design density while the 25 psf load is 17 inches. 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. The residential code of ohio which applies to one and two family homes shows a map indicating the required snow load. Simple design check representative of worst case combined axial and transverse loading.

It calls for 20 psf throughout most of ohio and 25 psf along a north south strip in the eastern half of the state. For example fresh snow is soft fluffy and light. Overestimation of snow loads can unnecessarily increase the cost of construction. 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.

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. 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.