Flat Roof Snow Load Equation

Ground snow load s s.

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. For ground snow loads greater than 20 pounds per square foot the roof load is equal to 70 of the product of the exposure thermal and importance factors the ground snow load and 20 pounds. But not less than the. Lets assume our project is in madison wisconsin and we have already calculated our balanced roof snow load here.

Determine the transient load 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. Rain load s r. Provisions on how to calculate the snow drift surcharge for structures can be found in section 7 8 of asce 7 10.

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. From our example our ground load and flat roof snow load were found to be 30 psf and 21 psf respectively. This is all of the natural stresses imposed upon a roof such as snow loads rain loads and wind loads. P f 0 7c e c t i p g.

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. If your structure has a sloped or flat roof you still need to calculate the flat roof snow load. 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.

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. Asce 7 05 equation 7 1 assumes that the snow load results from multiple events. Minimum flat roof snow load values. In regions with relatively low snow load values the load from a single event may result in the peak loading.

Importance factor i s. The following are the equation for determining snow loaing on flat roofs. Roof snow load nbc 2010 roof snow load nbc 2010 version 0 1 0 september 13 2020. As a result equation 7 1 which accounts for loss between events will result in a non conservative value.

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