How Much Snow Is Too Much On A Flat Roof

57 pounds a square foot.

How much snow is too much on a flat roof.

Roof collapse can happen to new and old buildings alike and can cause extensive damage to the building and contents. Fluffy fresh snow can weigh as little as three pounds per square foot compared with 21 pounds for wet heavy snow according to fema. It also helps if the roof is in a sheltered area. Low pitched and flat roofs are most susceptible to collapses.

Melting down a cubic foot of snow tells you how much water it holds and consequently how much the snow weighs. These questions aren t quite so easy to answer because there are several variables. A flat roof can be constructed to address the needs of the particular building regardless of location. And whenever it snows the flat roof supports an additional insulating blanket.

The weight of snow depends on how much water it contains. How much snow can your roof support. The r value or resistance to heat flow for snow is about r 1 per inch. Of snow equals about 1 to 1 1 2 psf.

So a risky roof is flat or slightly. As you know there is a big difference between a blizzard hitting your town and a dusting of snow. The snow settles on it evenly rather than being blown into large drifts which can cause a roof to fail. How much snow a roof can hold depends on the type of snow roofline and material among other considerations.

This is the one question that you need to answer. How much is too much. Most roof designs can handle snow loads of 20 40 lbs per square foot.