How Roof Pitch Affects Snow Load

7 factors in snow load evaluations.

How roof pitch affects snow load. How much snow a roof can hold depends on the type of snow roofline and material among other considerations. If your roof is pitched enter the length and width of the flat area covered by the roof. Pitched roof snow load calculator ask local authorities about the maximum snow expected to fall in your town. 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.

Roof pitch is especially significant for snow. You need to supply the following information. You can enter these values in any units you d like including meters and feet. Sloped roof snow loads are assumed to be acting on the horizontal projection of the surface.

Roof slope factor for multiple folded plate sawtooth and barrel vault roofs. When evaluating an existing roof for snow loads an engineer will want to know the year it was built the materials involved and the load the roof was designed to support to start. To calculate the weight of snow on a roof use the first two sections of our snow load calculator. Roof pitch may have the most apparent effect on snow accumulation.

It s quite obvious that flat or low slope roofs will collect more snow than ones with a steep pitch. If unbalanced snow loading isn t required or specified the truss designer may enter the 25 psf snow load as a top chord live load tcll set the load duration factor to 1 15 for snow and turn snow loading off completely. Or the 25 psf snow load could be entered as a roof snow load with the unbalanced snow loading option turned off. We re confident that our durable steel buildings can shoulder the load but accurate estimates and attention to detail will guarantee the safety of your steel building.

Wind loads must also be considered in your steel building design. When the roof slope is greater than 5 the roof is considered sloped. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow. These questions aren t quite so easy to answer because there are several variables.

P s c s p f. Length and width of your 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. Multiple folded plate sawtooth or barrel vault roofs shall have a c s 1 0 with no reduction in snow load because of slope i e p s p f.

The weight of one foot of fresh snow ranges from 3 pounds per square foot psf for light dry snow to 21 psf for wet heavy snow. Even roofs that are pitched as low as 10 degrees have shown to shed snow and rain at least a little bit. Ice dams and icicles along eaves. The sloped roof snow load is calculated using equation 7 4 1.