Roof Load Required For Snow

Roof loads are a downward vertical force on the home.

Roof load required for snow.

Loads are in pounds per square foot. Or the 25 psf snow load could be entered as a roof snow load with the unbalanced snow loading option turned off. In order to stay intact and in place a roof must be able to resist loads both permanent and temporary that are pushing. If unbalanced snow loading isn t required or specified the truss designer may enter the 25 psf snow load as a top chord live load tcll set the load duration factor to 1 15 for snow and turn snow loading off completely.

Snow loads shall be determined by the building official. 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 north zone middle zone and the south zone are identified on the roof load zone. Use ibc 2003 25 psf 300 psf and state of alaska has given authority to local building officials for determining required snow loads for their municipalities.

In areas of the state outside of certified city county and town jurisdictions the design snow load shall be based on the ground snow loads developed in snow loads for structural design in montana civil engineering department montana state university 2004 revised edition. Roof load live load design is affected by the shape of the roof whether it is flat curved or pitched. 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. Use ibc 2003 0 psf 10 psf with case study areas at higher elevations.

If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow. Modify these basic loads for wind shape of roof drifting ice loads etc. Roofs are under a lot of pressure. Use only within immediate vicinity of given town particularly if ground elevation changes noticeably.

However a south roof load zone home cannot be installed in either a middle or north roof load zone. Load limits on the roof of a building. A great deal of confusion currently exists among engineers architects recreation specialists and maintenance personnel concerning the proper snow loading to use for the design and maintenance of trail bridges building roofs and other structures in mountainous high snow load areas. Town load town load aguilar 40 idaho springs 50 alamosa 20 ignacio 40.

Recommended basic snow design loads snow loads by city 1. Once the ground snow load at the building site is determined it must then be converted to roof snow loads according to asce 7 with appropriate treatment of exposure to wind thermal properties of the roof roof slope unbalanced snow loads drifting and risk exposure. State snow load information alabama.