Roof Slope Factor Snow Load

Boca also allows you to reduce the snow load for roofs with slopes greater than 30 degrees presumably because snow will slide or blow off steeply pitched roofs.

Roof slope factor snow load.

If you want to calculate these values by hand use the following formulas. Snow loads roof snow loads are influenced by elevation general weather and moisture patterns slope direction exposure roof configuration and wind direction and severity. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow. All of the load cases required to fully design an actual structure are not provided by this.

If your structure has a sloped or flat roof you still need to calculate the flat roof snow load. P s c s p f the thermal factor c t from table e 3 determines if a roof is cold or warm slippery surface values shall be used only where the roof s surface is unobstructed and sufficient space is available below the eaves to accept all the sliding snow. Roof slope 0 degrees slope factor. The sloped roof snow load p s shall be obtained by multiplying the flat roof snow load p f by the roof slope factor c s.

This is the snow load calculated in the previous section. S 1 0 1 0 8 1 0 1 1 0 1 1 8kpa s 1 8 kpa s 37 6 psf. Once you know these values our snow load calculator automatically finds the total weight of snow on your roof. C s 1 uls.

For dead loads you are correct. 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. After you obtain the roof slope factor from those sections in asce 7 10 the balanced design snow load for the sloped roof can easily be calculated using equation 7 4 1. 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.

Snow load thickness density. Technically you should use the actual rafter length when adding up the weight of roofing materials. Roof snow load nbc 2010 version 0 1 0 september 13 2020. The balanced snow load is applied everywhere where the roof structure is located.

Overestimation of snow loads can unnecessarily increase the cost of construction.