Snow Weight On Flat Roof

Two feet of snow on a roof with a footprint of say 28 40 feet could weigh 45 000 pounds.

Snow weight on flat roof.

To calculate the weight of snow on a roof use the first two sections of our snow load calculator. Snow won t slide off. Estimate how much weight your roof can support. Estimate the weight of snow on your roof.

That s more than 22 tons. Ice and snow will typically accumulate more quickly on low slope and flat roofs. Local building codes dictate the snow load required for residential roofs. Damages snow causes to flat roofs ponding bowing.

What s the weight of snow on a roof. The roof deck collects the snow load and transfers the weight to the rafters. Length and width of your roof. Per square foot of roof space which is beyond the typical snow load capacity of most roofs.

If your roof is pitched enter the length and width of the flat area covered by the roof. 3 5 inches of old snow is equal to one inch of water or about 5 lbs. Two feet of old snow and two feet of new snow could weigh as much as 60 lbs. Per square foot of roof space so anything more than 2 feet of snow could be too much for your roof to handle.

You can enter these values in any units you d like including meters and feet. Flat roofs may be especially vulnerable to roof collapse depending on its engineered design load. Contact your local building code department to determine the snow load requirements for your area. House roofs should support 20 lbs square foot of snow before they become stressed.

For any rafter the portion of the roof deck that transfers this load is the tributary area. This down bearing pressure can cause the roof to bow and result in ponding under the roof structure.