Flat Roof Snow Load Equation

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 load equation.

Minimum flat roof snow load values. Lets assume our project is in madison wisconsin and we have already calculated our balanced roof snow load here. 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. In regions with relatively low snow load values the load from a single event may result in the peak loading.

From our example our ground load and flat roof snow load were found to be 30 psf and 21 psf respectively. 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. As a result equation 7 1 which accounts for loss between events will result in a non conservative value.

After you obtain the roof slope factor from those sections in asce 7 10 the balanced design snow load for the sloped roof can easily be calculated using equation 7 4 1. Flat roof snow load are determined by the following method. If your roof is flat it is more likely to have snow load problems than if it is pitched. You need to use a snow load formula for flat roofs.

Provisions on how to calculate the snow drift surcharge for structures can be found in section 7 8 of asce 7 10. If your structure has a sloped or flat roof you still need to calculate the flat roof snow load. P f 0 7c e c t i p g. 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.