Minimum Angle Of Roof Pitch

Asphalt shingles minimum roof slope roof pitch r905 2 2.

Minimum angle of roof pitch.

The minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run. It is uncommon to find a roof below 15 but for those very low pitch applications there are interlocking clay pantiles available suitable for use down to 12 5. 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. This means that the rise of the slope goes up or down 8 inches for every 12 inches.

In order to achieve this drop a slightly steeper angle of 1 40 1 44 should be the aim when installing a flat roof as this accounts for surface. 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. Although there s isn t any standard pitch of a roof used on all kinds of sloped roofs you can determine the range of pitches by using a roof angle calculator and by considering factors like the local climate and roofing materials. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.

Asphalt shingles can only be installed on roof slopes of 2 12 or greater. To put it in perspective the angle of this slope would be around 30 degrees. 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. The minimum roof pitch is also subject to the standards set forth by the various building codes used in the respective regions.

The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. Asphalt shingles continue to be the most widely installed roof covering option in north america. An example for a steep sloped roof is 8 12. They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.

However you can only use this pitch with built up roofing or specialized synthetic roofing. Normally 1 80 0 72 is the recommended minimum angle for a slope and this is universal across the vast majority of flat roofing systems regardless of the materials that they incorporate. This means for every 12 horizontal units the roof must rise a minimum of 2 vertical units. The slope of a roof or pitch is determined by how many inches the roof rises over 1 foot or 12 inches.

Importance of a roof pitch.