Flat Roof Snow Load Formula

The equation for converting ground snow load p g to roof snow load p f is asce 7 05 equation 7 1.

Flat roof snow load formula.

Live roof load w wind load s snow load e earthquake load r rainwater load or ice water load t effect of material temperature h hydraulic loads from soil f hydraulic loads from fluids arch 331 note set 13 1 s2014abn 2 determining dead load from material weights. 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. 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. For ground snow loads greater than 20 pounds per square foot the roof load is equal to 70 of the product of the exposure thermal and importance factors the ground snow load and 20 pounds.

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. This is all of the natural stresses imposed upon a roof such as snow loads rain loads and wind loads. Snow weight length width cos pitch snow load the weight of snowis measured in kgor lbs. P g ground snow load l u length of upper roof l l length of lower roof h d height of snow drift w width of snow drift h b height of balanced snow load h c clear height from top of balanced snow load to closest point of adjacent roof h r height difference between roofs.

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. Snow load thickness density the result snow load or the pressure exerted by the snow has the units of kn m or lbs ft. Online snow load calculator for buildings with flat or low slope roofs for balanced snow drift and rain on snow surcharge loadings calculator asce 7 05 for structural engineers construction professionals and building planners. 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.

Determine the transient load of the roof. Consequently the roof design snow load is taken to be less than the ground snow load. This equation includes factors that take into account exposure and building heat loss. Step 4 determine the flat roof snow load.

The balanced snow load is applied everywhere where the roof structure is located.