Slope Roof Snow

In general determining the pitch of an existing roof is a simple calculation.

Slope roof snow.

This can be accomplished by measuring the number of inches the roof rises vertically for every 12 inches it extends horizontally. The minimum roof pitch for shedding snow is around 30 or a 6 12 or 7 12 slope although this is not a definite as the material of your roof the direction of the snow and wind are some factors that can affect whether or not snow will slide as roofs of as little as 10 have been reported to shed snow. There are some opinions that standing seam metal roof minimum slope is 12 but it increases the possibility of leaking on the few first days of snow arrival. In country with heavy snow and tough winter days the metal roof minimum slope is recommended to be 1 12.

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. What exactly is roof slope. You can enter this value either as a ratio x 12 or as an angle whichever suits you better. The chief reason for having a roof pitch is to redirect water and snow away from the roof and avoid any percolation that might result from stagnation of water on the roof.

P s c s p f 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. Roof slopes are most commonly defined by the rise over run ratio. If a roof slope rises say 4 inches when measured 12 inches along the bottom of a horizontal roof truss the roof slope is said to be 4 12. The way pitch also known as roof slope is measured is rise over run.

Flat roofs are common with industrial buildings boasting wide roof spans and are also popular in dry climates for houses where there is no need for the roof to help disperse rain and snow. I e 4 inches of rise per 12 inches one foot of run. If your roof is pitched enter the length and width of the flat area covered by the roof. So if your roof rises 4 inches for every 12 inches of horizontal length then the pitch of your roof is expressed as 4 12.

For example a roof with a 6 inch 12 pitch is one where it rises 6 inches vertically for every 12 inches of the horizontal run. Importance of a roof pitch. The minimum roof pitch is also subject to the standards set forth by the various building codes used in the respective regions. Intuitively this is the number of inches of snow on your roof in the place where the cover is the thickest.