Flat Roof Snow Load Equation

The following are the equation for determining snow loaing on flat roofs.

Flat roof snow load equation.

From our example our ground load and flat roof snow load were found to be 30 psf and 21 psf respectively. If your roof is flat it is more likely to have snow load problems than if it is pitched. 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. First figure out how deep the snow is piled up there.

Provisions on how to calculate the snow drift surcharge for structures can be found in section 7 8 of asce 7 10. In regions with relatively low snow load values the load from a single event may result in the peak loading. Lets assume our project is in madison wisconsin and we have already calculated our balanced roof snow load here. 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.

As a result equation 7 1 which accounts for loss between events will result in a non conservative value. You need to use a snow load formula for flat roofs. Flat roof snow load are determined by the following method. Minimum flat roof snow load values.

If your structure has a sloped or flat roof you still need to calculate the flat roof snow load. Asce 7 05 equation 7 1 assumes that the snow load results from multiple 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. The snow load p f on a roof with a slope equal to or less than 5 degrees 1 in ft 4 76 deg shall be calculated in lb ft 2 kn m 2 using the following formula.