Flat Roofs And Snow Load

Wind seismic building weight furniture occupants etc.

Flat roofs and snow load.

In regions with relatively low snow load values the load from a single event may result in the peak loading. There are a few common misconceptions regarding flat roofs that are stubbornly persistent. Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10. Certainly the weight of snow can add up but your home must support a variety of loads.

Minimum flat roof snow load values. You need to use a snow load formula for flat roofs. The flat roof snow load is calculated using formula 7 3 1. The snow load that is applied to our structure is not the ground snow load but in most cases the flat roof snow load.

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 is actually one of the easiest to design for and all. Another is that they cannot handle as much snow weight as pitched roofs because the snow sits directly on the roof. Asce 7 05 equation 7 1 assumes that the snow load results from multiple events.

Flat roofs can t possibly support all the extra weight a totally valid concern but rest assured your architect and engineer have this in mind when designing the roof structure. First figure out how deep the snow is piled up there. 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. For example 18 inches would be 1 5 feet.

One of them is that flat roofs leak more easily than pitched ones.