Snow Load On Sloped Roof

Flat roof snow loads p f.

Snow load on sloped roof. Roof snow load is defined as the weight of snow on the roof surface used in design of the building structure ibc 2012. If you want to calculate these values by hand use the following formulas. Sloped roof snow. Ground snow load value.

A great deal of confusion currently exists among engineers architects recreation specialists and maintenance personnel concerning the proper snow loading to use for the design and maintenance of trail bridges building roofs and other structures in mountainous high snow load areas. The effect of snow loads on a structure can have dire. The sloped roof snow load p s shall be obtained by multiplying the flat roof snow load p f by the roof slope factor c s. Boca also allows you to reduce the snow load for roofs with slopes greater than 30 degrees presumably because snow will slide or blow off steeply pitched roofs.

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. Snow loads acting on a sloping surface shall be assumed to act on the horizontal projection of that surface. Calculating roof snow loads w asce 7 10 a walk through on how to calculate roof snow loads per asce 7 10. For dead loads you are correct.

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. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow. 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. It makes sense when designing a metal roof to shed snow not to keep it on.

Technically you should use the actual rafter length when adding up the weight of roofing materials. Discount that actual snow loads may exceed them only that the risk of snow load induced failure is reduced to an acceptably low level. On multiple factors including. Once you know these values our snow load calculator automatically finds the total weight of snow on your roof.

The thermal factor c t from table e 3 determines if a roof is cold or warm slippery surface values shall be used only where the roof s surface is unobstructed and sufficient space is available below. It is determined based. P s c s p f. 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.

The snow load that is applied to our structure is not the ground snow load but in most. To do this i use conservative too heavy dead loads and full snow loads regardless of pitch. However in my practice i typically use the horizontal run of the roof for both types of load. Snow loads are influenced by elevation general weather and moisture patterns slope direction exposure roof or trail bridge configuration and wind direction and severity.

It is critical that a designer specify enough snow retention devices based on the slope and snow load.