Snow Load Flat Roof Design

D dead load l live load l r live roof load w wind load s snow load e earthquake load r rainwater load or ice water load t effect of material temperature.

Snow load flat roof design.

The design snow load represents the peak snow accumulation on a roof over the a winter season. In colder regions the design snow load represents snow deposited by multiple snow events. 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. Snow loads acting on a sloping surface shall be assumed to act on the horizontal projection of that surface.

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. You need to use a snow load formula for flat roofs. If your roof is flat it is more likely to have snow load problems than if it is pitched. Location 2uniform load psf kn m roofs ordinary flat pitched and curved roofs.

Once you have the ground snow load p g you can compute the flat roof snow load p f. Loads used in design load equations are given letters by type. Online snow load calculator for buildings with flat or low slope roofs for balanced snow drift and rain on snow surcharge loadings calculator asce 7 05 for structural engineers construction professionals and building planners. Flat roof snow loads p f the snow load that is applied to our structure is not the ground snow load but in most cases the flat roof snow load.

In our case let s assume that our structure has a flat roof roof slope 5. In areas where the ground snow load p g exceeds 10 pounds per square foot psf 0 479 kn m 2 the following additional information shall also be provided regardless of whether snow loads govern the design of the roof. If you have any concerns as you are determining your flat roof snow load consult with a structural engineer or roofing specialist. P s c s p f.

The easiest way is to push a yardstick into the snow on the roof selecting an area that looks typical of the overall snow depth. Snow exposure factor c e. Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10. Sloped roof snow loads calculations and regional design.

A flat roof is no more or less likely to leak than a pitched roof it all comes down to the design and the competence with which it is installed. Flat roofs must be installed on a very specific mild slope so that the water can drain off properly and if the drains and scuppers aren t cleared regularly this increases the chance of a leak. This may also be true in some more moderate climates as well. Snow load importance.

First figure out how deep the snow is piled up there.