Normal Roof Slopes

The minimum slope for lapped non soldered seam metal roofs with applied lap sealant shall be one half unit vertical in 12 units horizontal 4 percent slope.

Normal roof slopes.

The minimum slope for lapped non soldered seam metal roofs without applied lap sealant shall be three units vertical in 12 units horizontal 25 percent slope. According to this code the minimum slope for asphalt shingles is 17 degrees or two vertical units to twelve units in the horizontal. Often found on church towers. Pitches above 9 12 are very highly angled and are designated steep slope roofs.

Pyramid roof pavilion roof. Pitches lower than 4 12 have a slight angle and they are defined as low slope roofs. Tented a type of polygonal hipped roof with steeply pitched slopes rising to a peak. If the rise is 6 inches for every 12 inches of run then the roof slope is 6 in 12 the slope can be expressed numerically as a ratio.

A handy roof slope estimator can help you determine if your roof slope is likely too low for shingles. 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. The most commonly used roof pitches fall in a range between 4 12 and 9 12. Roofs at the lower end of the range about 4 12 to 6 12 are relatively easy to walk and work on.

A hip roof on a square building. A roof slope of 7 12 is also good and can provide the additional benefit of helping minimize the effects of wind driven rain. Helm roof rhenish helm. You can also divide the rise over run multiply by 100 and get a percentage.

Thus a 4 12 pitch would be a 33 slope. The majority of north american residential roofs have historically been constructed with a slope between about 4 12 and 9 12. The typical roof slope follows specific materials and design techniques to ensure perfect safety from leakage. A 4 12 pitch is around 18 5 degrees but not exactly.

The requirements for an asphalt shingles roof are contained in the international building code. Roof slopes between 4 12 and 6 12 are best for minimizing the wind uplift effects in high wind zones. The slope ratio represents a certain amount of vertical rise for every 12 inches of horizontal run. Pitches of less than 2 12 are considered flat roofs even though they may be very slightly angled.

A ratio is the most common way of expressing roof pitch or roof slope but degrees are also possible. A common range is given from 1 12 to 4 12 whereas conventional dimensions vary from 4 12 to 9 12 but the steep roofing technique follows slope above 9 12 with additional fasteners. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.