Pitch Of Roof For Snow

Low pitch roofs are easier to install and safer to walk around to complete repairs and maintenance.

Pitch of roof for snow.

This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. Low pitch roofs are seldom used in regions of severe weather due to the stress of snow accumulation on roofs of structures. The table below shows common roof pitches and the equivalent grade degrees and radians for each. Others allow a 1 4 inch slope.

This is fortunate since flat roofs are somewhat more prone to leaks and require frequent inspections. You can enter this value either as a ratio x 12 or as an angle whichever suits you better. This can be accomplished by measuring the number of inches the roof rises vertically for every 12 inches it extends horizontally. 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.

When the snow piled up on the roof melting occurred and ice dams resulted in water ponding 3 inches deep. The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7. A pitch over 9 12 is considered a steep slope roof between 2 12 and 4 12 is considered a low slope roof and less than 2 12 is considered a flat roof. A 1 4 inch slope may work in alabama but one can expect leaks in minnesota or.

In country with heavy snow and tough winter days the metal roof minimum slope is recommended to be 1 12. 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. In general determining the pitch of an existing roof is a simple calculation. 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.

If your roof is pitched enter the length and width of the flat area covered by the roof. Intuitively this is the number of inches of snow on your roof in the place where the cover is the thickest. Metal roofs leak under these circumstances. Some metal building manufacturers will not warranty a roof with a 1 4 inch slope.