Snow Load Psf Roof

C s roof slope factor p f flat roof snow load.

Snow load psf roof.

P s c s p f where. In areas of the state outside of certified city county and town jurisdictions the design snow load shall be based on the ground snow loads developed in snow loads for structural design in montana civil engineering department montana state university 2004 revised edition. The sloped roof snow load is calculated using equation 7 4 1. When the roof slope is greater than 5 the roof is considered sloped.

If you want to calculate these values by hand use the following formulas. Roof snow loads indicate the amount of additional force pressing down on a building when snow and ice pile up on the roof during winter storms. Or the 25 psf snow load could be entered as a roof snow load with the unbalanced snow loading option turned off. That sounds simple enough right.

Once you know these values our snow load calculator automatically finds the total weight of snow on your roof. Roof slope factor c s. You can also find the load per square meter or square foot of roofing by opening the advanced mode. In areas of the state outside of certified local government jurisdictions the design snow load shall be based on the ground snow loads developed in snow loads for structural design in montana authored by f f.

Sloped roof snow loads are assumed to be acting on the horizontal projection of the surface. Allowing for the snow that blows off the actual design load can typically be reduced to 14 psf. Schilke civil agricultural engineering montana state university august 1989. The minimum design roof snow load after allowed reductions shall be 30 psf.

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. Snow loads shall be determined by the building official. This is considerably less than the 25 psf that the old codes required. Snow load thickness density.

Well there are a lot more variables than just the amount of snow on the roof. Sliding snow from a sloped roof. Density the density of the snow makes a significant difference in the weight of the snow. The design roof snow load for residential buildings in mn is set by state statutes and is 42 pounds per square foot psf in northern mn and 35 psf in southern mn.