Suggested Snow Roof Degree

A reputable roofing contractor will be familiar with the pitch required by these codes.

Suggested snow roof degree.

The requirements for an asphalt shingles roof are contained in the international building code. S equals the depth in inches of the snow on your roof and p represents the pounds per square foot your roof is supporting. And although asphalt shingles are the easiest to damage among the roofing materials they are another good option for snow as long as your climate isn t too windy. On roof slopes between 4 12 and 6 12 rough textured roofing materials work best.

Roof slopes lower than 4 12 tend to perform well with metal roofs which are less prone to leakage and ice dam formation. Slate is also a popular material in this climate zone. 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. The pitch of the roof is determined by the vertical rise.

Pitch is a measure of the steepness of a roof. Steeper slopes increase the sail effect that makes them susceptible to wind. According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal. The 30 degree 7 12 roof recommendation is backed up by testing according to the publication science daily.

In snowy areas your roof should be at least 10 12 40 to allow snow to shed while the safest roof pitch in very windy areas is between 4 12 6 12 18 5 26 5. Your equation for determining snow load s x 1 25 p is fairly straightforward math. At these slopes snow creeps rather than slides and is easy to manage. A 30 degree roof slope 7 12 pitch is the right pitch to aerodynamically handle high wind.

To calculate the snow load on your roof assume that every inch deep of snow equals 1 25 pounds. Determining the roof pitch for your weather the first thing to do is to check the building codes for your county and state. In country with heavy snow and tough winter days the metal roof minimum slope is recommended to be 1 12.