Minimum Roof Slope For Snow

The key factors are usually snow loading requirements adequate slope and the use of snow guards when needed.

Minimum roof slope for snow.

In country with heavy snow and tough winter days the metal roof minimum slope is recommended to be 1 12. 18 43 asphalt shingles with special underlayment requirements 2 in 12. The minimum pitch for shingles is 1 6 which is equivalent to 4 inches rise to 24 inches run. Metal roofing systems have a good track record of performance in harsh winter environments as long as they are properly designed.

People have been killed by snow avalanches sliding off roofs during big snow winters. Minimum required roof slope for roofing materials. Minimum pitch for corrugated metal roof. 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.

Determine the minimum slope of the roof based on the roofing material. According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal. A minimum slope of 1 inch per foot is recommended in snow country. Intuitively this is the number of inches of snow on your roof in the place where the cover is the thickest.

Roofing material or system. Begin by measuring 12 inches on your level and marking it with a pencil. Minimum required slope x in 12 minimum required slope degrees asphalt shingles. 9 46 built up roof asphalt.

You can enter this value either as a ratio x 12 or as an angle whichever suits you better. In 12 0 25 in 12 1 19 built up roof coal tar pitch. They hold the snow in place and keep it from accumulating and then sliding off in large slabs that can be dangerous. In case a slope greater than this is necessary then a double underlayment application must be used as per the requirements of the international building code.

You can safely measure the roof pitch from inside your attic with a level that is either 18 or 24 inches a tape measure and a pencil.