Ground Snow To Roof Sno

The determination of the drift load that is required for unbalanced snow load cases requires the use of the ground snow load pg not the roof snow load.

Ground snow to roof sno.

In my region on cape cod we have a ground snow load design of 25 psf which is a greater design load than the live load 12 psf to 20 psf over an entire roof system. Pf is flat roof snow load if as a consumer your concern is snowfall and you want to upgrade the ability of your building to carry it this is the value to increase. 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. Often changes of five or 10 pounds per square foot result in minimal differences in cost.

Posted at december 21 2014 in technical. In other words on a steep roof less material would be stacked in a concentrated area at one time to avoid having it slide off. Site designed and maintained by york digital solutions inc. Return to top.

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. P s c s p f. Snow can either blown from the low side of the roof towards the high side or is blown off the higher area of the roof onto the lower projected side. The density of snow and hence its load per square foot depends on the type of snow.

Roof and building data. Leeward drift results from snow blown off a high roof onto a lower roof. Typically the leeward drift height hdl is greater than the windward drift height hdw unless the length of the lower roof is considerably longer than the length of the upper roof. Psf 5 psf 300 psf roof pitch.

Thermal factor c t. On the other hand snow that stayed on your roof for a few days will settle and while it seems that the cover gets thinner its weight doesn t change it s just the density that is different. 1995 ground snow load table. Ground snow load values for ontario and quebec.

0 7 x ce x ct x is x pg pf. 2010 ground snow load table for quebec. Ground snow load p g. If your roof is 1 000 square feet the total snow load is 15 000 pounds of snow.

If the ground snow load isn t specified then a ground snow load needs to be assumed and the truss designer and the building designer may not be on the same page as it relates to this design assumption. Required data design assumptions. Pg is converted to pf by this formula. Snow loads acting on a sloping surface shall be assumed to act on the horizontal projection of that surface.

For example fresh snow is soft fluffy and light. The amount of additional snow load or surcharge depends on the difference in height of the two adjacent roofs and the lengths of roof perpendicular to the drop in height.