Snow Pressure On Roof

Slipperiness of the roof.

Snow pressure on roof.

10 12 inches of new snow is equal to about one inch of water or about 5 pounds per square foot of roof space so you could have up to 4 ft. I i i i i i i i i i i i i i i i i i i ground and roof snow loads. To figure out the load on your roof take the depth of snow in feet and multiply it by the weight of a cubic foot of snow. View of the upper roof adjacent to the skylights after removal of the drift.

3 roof maintenance. If the snow weighs 10 pounds per cubic foot and there are 1 5 feet on the roof each square foot of the roof is getting 15 pounds of pressure. View of another area where drifts were removed. Roof snow loads for idaho universityotldaho department of civil engineering moscow idaho 83843 r.

Note the shovel marks on the snow indicating that some snow was deliberately left over the roof membrane. The key purpose of a snow retention system is to hold and retain snow ice on the roof and allow a controlled evacuation of the snow which will help protect your assets and decrease your liability. 4 2 lateral snow pressure. Roofs under pressure from too much heavy snow are at risk of.

For locations where 0 pg 20 psf all roofs with a slope w 50 with w in ft shall have a 5 psf rain on snow surcharge. A properly designed and installed system will retain the snow on the roof and prevent damage to gutters signage lighting landscaping canopies. This rain on snow augmented design load applies only to the balanced load case and need not be used in combination with drift sliding unbalanced or partial loads. If your roof is located in windswept areas or even north of the treeline the wind will cause snow drifting making less of it accumulate on your roof.

If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow. Thus snow weighing 10 pounds per cubic foot and at a depth of 18 inches on a roof is exerting 15 pounds of pressure per square foot. Structural damage ice dams causing roof rot damage to flashing and gutters etc collapse. Less snow will accumulate on a slippery roof it will slide off instead.