Minimum Roof Slope For Snow Load

If you live in the us our snow load calculator compares the total weight on your roof with the permissible load calculated according to the standards issued by the american society of civil engineers regarding the minimum design loads for buildings and other structures asce7 16.

Minimum roof slope for snow load.

Values of c s for warm roofs and cold roofs are as. 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. The sloped roof snow load is calculated using equation 7 4 1. P s c s p f.

All commercial buildings and structures should use the ground snow load values from the 2009 ibc and not the residential design values given below. So you do not multiply cs by the minimum pf for sloped roofs. According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal. 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.

Keep in mind that neither metal shingles not corrugated metal panels are suitable options for low slope or nearly flat roofs. Roof design snow loads derived from figure 321 02 of the wisconsin. All snow loads acting on a sloping surface shall be considered to act on the horizontal projection of that surface. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow.

Btw i think there is some confusion on what i m saying about the 7 factor. In case a slope greater than this is necessary then a double underlayment application must be used as per the requirements of the international building code. You multiply it by whatever equation 7 1 gives you. A steep slope roof is one whose slope is greater than 3 12.

B sloped roof snow loads ps. P s cspf equation 68 5 3. For example a roof with a 6 inch 12 pitch is one where it rises 6 inches vertically for every 12 inches of the horizontal run. Suitable materials for pitched roofs.

Sloped roof snow loads are assumed to be acting on the horizontal projection of the surface. When it comes to residential construction your roof is a visible part of the structure. Okay i just got the word from a highly placed source that the minimum snow load provision only applies to low slope roofs. Minimum pitch for corrugated metal roof.

Steeper slopes are ideal for areas that have higher snow loads and will also prevent the possibility of ponding water on the roof. Pitched roofs begin with with slopes greater than 3 in 12. A minimum pitch of 3 in 12 or even 4 in 12 will normally be required. You can click on the map below to find the minimum roof design snow load for that location.

When the roof slope is greater than 5 the roof is considered sloped.