Ground Vs Roof Snow Oad

Sheikh taheri through years of research.

Ground vs roof snow oad.

In my region on cape cod we have a ground snow load design of 25 psf which is a greater design load than the live load 12 psf to 20 psf over an entire roof system. The bottom line is that the irc requires you to design the roof structure to the greater roof load and in my region that s the ground snow load. 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. Purpose of this web site.

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 snow load that is applied to our structure is not the ground snow load but in most cases the flat roof snow load. Horizontal distance from eave to ridge. Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10.

The purpose of this web site is to provide ground snow load analysis information and data gathered from all 50 states. 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. 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.

Weight of permanent. Length of roof upwind of the snow drift. 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. Ground snow load pg.

In our case let s assume that our structure has a flat roof roof slope 5. 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. Length of roof downwind of the snow drift. 70 60 50 40 35 30 25 x0 7 x0 7 x0 7 x0 7 x0 7 x0 7 x0 7 roof snow load.

Snow loads can be presented in two different ways. The determination of the drift load that is required for unbalanced snow load cases requires the use of the ground snow load pg not the roof snow load. Ground snow load or roof snow load snow load. 49 42 35 28 24 5 21 17 5 assumed value thermal factor ct.

It was released in 1986 by the department of civil engineering at the university of idaho. Figure 7 1 pages 84 85 and table 7 1 page 92. From eave to ridge w. The flat roof snow load is calculated using formula 7 3 1.

1 0 exposure factor ce. 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. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow.