Snow Weight On Flat Roof

Estimate how much weight your roof can support.

Snow weight on flat roof.

Local building codes dictate the snow load required for residential roofs. Per square foot of roof space so anything more than 2 feet of snow could be too much for your roof to handle. Length and width of your roof. For any rafter the portion of the roof deck that transfers this load is the tributary area.

Per square foot of roof space which is beyond the typical snow load capacity of most roofs. Since snow falls at slow steady speeds large quantities of snow can fall on the roof resulting in bowing. 3 5 inches of old snow is equal to one inch of water or about 5 lbs. What s the weight of snow on a roof.

Estimate the weight of snow on your roof. To calculate the weight of snow on a roof use the first two sections of our snow load calculator. This down bearing pressure can cause the roof to bow and result in ponding under the roof structure. Contact your local building code department to determine the snow load requirements for your area.

Snow won t slide off. Flat roofs may be especially vulnerable to roof collapse depending on its engineered design load. Two feet of snow on a roof with a footprint of say 28 40 feet could weigh 45 000 pounds. If your roof is pitched enter the length and width of the flat area covered by the roof.

You can enter these values in any units you d like including meters and feet. As snow falls it can accumulate on your flat roof putting unnecessary weight on the structure. The roof deck collects the snow load and transfers the weight to the rafters. Damages snow causes to flat roofs ponding bowing.

Ice and snow will typically accumulate more quickly on low slope and flat roofs. House roofs should support 20 lbs square foot of snow before they become stressed.