How Much Snow Is Too Much On A Flat Roof

The snow settles on it evenly rather than being blown into large drifts which can cause a roof to fail.

How much snow is too much on a flat roof. It also helps if the roof is in a sheltered area. Of snow equals about 1 to 1 1 2 psf. How much is too much. Melting down a cubic foot of snow tells you how much water it holds and consequently how much the snow weighs.

The weight of snow depends on how much water it contains. These questions aren t quite so easy to answer because there are several variables. This is the one question that you need to answer. Fluffy fresh snow can weigh as little as three pounds per square foot compared with 21 pounds for wet heavy snow according to fema.

57 pounds a square foot. 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. And whenever it snows the flat roof supports an additional insulating blanket. If that sounds a little involved the national research council of canada estimates that 1 in.

How much snow can your roof support. As you know there is a big difference between a blizzard hitting your town and a dusting of snow. Low pitched and flat roofs are most susceptible to collapses. Most roof designs can handle snow loads of 20 40 lbs per square foot.

So a risky roof is flat or slightly. The r value or resistance to heat flow for snow is about r 1 per inch. A flat roof can be constructed to address the needs of the particular building regardless of location.