Flat Roof Snow

That means 12 inches of snow on a flat roof creates an additional r 12 of insulation that arrives at a time of year when you most need it.

Flat roof snow. Another is that they cannot handle as much snow weight as pitched roofs because the snow sits directly on the roof. Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10. The flat roof snow load is calculated using formula 7 3 1. Snow melting flat roofs requires high output over a large surface area due to the heat transfer properties of gravel.

A thermapanel system can be installed on the roof and beneath the gravel and deliver enough heat to melt the snow load. When water from that melted snow works its way to the edges of your roof where it isn t as warm and then re freezes it can also form ice dams. First figure out how deep the snow is piled up there. If your roof is flat it is more likely to have snow load problems than if it is pitched.

This down bearing pressure can cause the roof to bow and result in ponding under the roof structure. As snow falls it can accumulate on your flat roof putting unnecessary weight on the structure. In our case let s assume that our structure has a flat roof roof slope 5. With a flat roof you don t have the typical attic space afforded by a sloped roof.

The r value or resistance to heat flow for snow is about r 1 per inch. Since snow falls at slow steady speeds large quantities of snow can fall on the roof resulting in bowing. Radiant tubing technology just can t get enough energy to the surface to effectively melt snow. While not frequent per se the low slope of a flat roof does make it more prone to certain problems particularly when it interacts with the elements.

Without that space heat inside your house can warm up your roof melting any snow that s piled up. Excessive rain heavy snow and built up ice all pose extra challenges for flat roofed homes. You need to use a snow load formula for flat roofs. And whenever it snows the flat roof supports an additional insulating blanket.

Snow and your flat roof there are a few common misconceptions regarding flat roofs that are stubbornly persistent. For roofs that are flat and with ground snow loads lower than 20 pounds per square foot the roof snow load is equal to 70 of the product of the exposure thermal and importance factors and the ground snow load.