Suggested Snow Roof Degree

Lower slopes don t handle wind driven rain as well.

Suggested snow roof degree.

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. If you live in the us our snow load calculator compares the total weight on your roof with the permissible load calculated according to the standards issued by the american society of civil engineers regarding the minimum design loads for buildings and other structures asce7 16. The pitch of the roof is determined by the vertical rise. A reputable roofing contractor will be familiar with the pitch required by these codes.

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. At these slopes snow creeps rather than slides and is easy to manage. Pitch is a measure of the steepness of a roof.

Determining the roof pitch for your weather the first thing to do is to check the building codes for your county and state. Your equation for determining snow load s x 1 25 p is fairly straightforward math. According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal. In country with heavy snow and tough winter days the metal roof minimum slope is recommended to be 1 12.

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. Steeper slopes increase the sail effect that makes them susceptible to wind. S equals the depth in inches of the snow on your roof and p represents the pounds per square foot your roof is supporting. Building a roof with wood shakes works well in moist colder climates as they don t dry out from the 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. To calculate the snow load on your roof assume that every inch deep of snow equals 1 25 pounds. The requirements for an asphalt shingles roof are contained in the international building code.