How Much Does Snow Weigh On A Roof

For any rafter the portion of the roof deck that transfers this load is the tributary area.

How much does snow weigh on a roof.

Fresh light and fluffy snow will weight much less than the dense packed or wet variety. Fluffy fresh snow can weigh as little as three pounds per square foot compared with 21 pounds for wet heavy snow according to fema. Drifting snow can put excessive loads on the areas where it piles up such as. How much does snow weigh on a roof.

Here are a few examples of the weight of snow on a roof. Unsurprisingly wet snow is the heavy stuff. Before the snow starts to fall and build up on the roof of your house take the time to know how much snow your roof can support. Psf pounds per square foot.

1 foot of snow on the roof 8 000 lbs 4 tons 7 psf 2 feet of snow on the roof 16 000 lbs 8 tons 14 psf 3 feet of snow on the roof 24 000 lbs 12 tons 21 psf. Per square foot of roof space so anything more than 2 feet of snow could be too much for your roof to handle. Calculating snow load on roof. 28 40 light fluffy snow.

All numbers are approximate. If it snows 5 of wet snow it will weigh about 12 5 pounds. 3 5 inches of old snow is equal to one inch of water or about 5 lbs. With this information you re now likely wondering about the weight of snow load on your roof.

Per square foot of roof space which is beyond. If you live in the us our snow load calculator compares the total weight on your roof with the permissible load calculated according to the standards issued by the american society of civil engineers regarding the minimum design loads for buildings and other structures asce7 16. How much does snow weigh. Two feet of old snow and two feet of new snow could weigh as much as 60 lbs.

Rain falling on accumulated snow will add more weight. This kind of snow will weigh around 7 pounds per cubic foot. Dry fluffy snow is the least concern with respect to weight. Evaluate your risk of roof top snow ice accumulation snow usually melts off of steep sloped roofs slopes greater than 3 inches of slope in 12 inches of horizontal distance more quickly than flatter roofs.

Calculating snow load on your roof depends on two factors. The roof deck collects the snow load and transfers the weight to the rafters. Calculating the weight of snow is useful when you need to know the total weight it adds for example to calculate the weight on a roof. Snow which is just frozen ice crystals varies in weight by its volume and density.

57 pounds a square foot. There is a calculation for this too. A cubic foot of snow can weigh from seven pounds for snow that is new and dry to 30 pounds for old compacted snow.