Roof Slope Factor For Snow Load

Residential roof with asphalt wood shingles or shakes would use fig.

Roof slope factor for snow load.

R802 10 2 and designed according to the minimum requirements of asce 7 10. This rain on snow augmented design load applies only to the balanced load case and need not be used in combination with drift sliding unbalanced or partial loads. 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. For locations where 0 pg 20 psf all roofs with a slope w 50 with w in ft shall have a 5 psf rain on snow surcharge.

Calculate sloped roof snow load p s using the following equation. All of the load cases required to fully design an actual structure are not provided by this calculator. If your structure has a sloped or flat roof you still need to calculate the flat roof snow load. For dead loads you are correct.

P s sloped roof snow load in psf c s roof slope factor as determined by asce sec. 7 4 1 7 4 4 and asce figure 7 2 below. 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. Once you know these values our snow load calculator automatically finds the total weight of snow on your roof.

Slope 30 degrees. 7 2b with a c s 1 0 p f flat roof snow load in psf. 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. 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.

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. Roof slope 0 degrees slope factor. For the design of an actual structure a registered and licensed professional should be consulted as per irc 2012 sec. Snow load thickness density.

C s 1 uls. Roof snow load nbc 2010 version 0 1 0 september 13 2020. 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.

The balanced snow load is applied everywhere where the roof structure is located. 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. P s c s p f where.