Ground Vs Roof Snow Oad

Purpose of this web site.

Ground vs roof snow oad.

If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow. 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. 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 basis for the snow load computation in asce 7 05 is the ground snow load.

The value used for the ground snow load should represent the snow load that has a 50 year mean recurrence interval or in other words a 2 probability of being exceeded in any given year. Length of roof upwind of the snow drift. Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10. Pf is flat roof snow load if as a consumer your concern is snowfall and you want to upgrade the ability of your building to carry it this is the value to increase.

This issue of live load vs. Victor staley a building official in the town of brewster mass responds. 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. Length of low roof ll.

When discussing snow load with anyone it is crucial to have a clear understanding as to if the load is a ground or flat roof snow load. Length of high roof lu. The snow load that is applied to our structure is not the ground snow load but in most cases the flat roof snow load. Asce 7 drift height calculation.

From eave to ridge w. The roof shall be designed for the live load indicated in table r301 6 or the snow load indicated. Ground snow load pg. Horizontal distance from eave to ridge.

The flat roof snow load is calculated using formula 7 3 1. In our case let s assume that our structure has a flat roof roof slope 5. Length of roof downwind of the snow drift. Even when the specification is clear regarding ground snow vs.

Roof snow load and the applicable snow. If the ground snow load isn t specified then a ground snow load needs to be assumed and the truss designer and the building designer may not be on the same page as it relates to this design assumption. Each state has a listing of building code and applicable guidelines for snow loads as well as details about where the snow load information may be found or purchased.