Calculate sloped roof snow load p s using the following equation.
Roof slope factor for snow load.
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.
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.
C s 1 uls.
R802 10 2 and designed according to the minimum requirements of asce 7 10.
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.
7 2b with a c s 1 0 p f flat roof snow load in psf.
Roof snow load nbc 2010 version 0 1 0 september 13 2020.
For dead loads you are correct.
All of the load cases required to fully design an actual structure are not provided by this calculator.
7 4 1 7 4 4 and asce figure 7 2 below.
For the design of an actual structure a registered and licensed professional should be consulted as per irc 2012 sec.
P s sloped roof snow load in psf c s roof slope factor as determined by asce sec.
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.
Slope 30 degrees.
Residential roof with asphalt wood shingles or shakes would use fig.
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.
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.
P s c s p f where.
This is the snow load calculated in the previous section.
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.
If you want to calculate these values by hand use the following formulas.
S 1 0 1 0 8 1 0 1 1 0 1 1 8kpa s 1 8 kpa s 37 6 psf.
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.
You can also find the load per square meter or square foot of roofing by opening the advanced mode.
If your structure has a sloped or flat roof you still need to calculate the flat roof snow load.
The boca code recognizes this and allows you to use the horizontal projection of the roof when calculating snow loads.
