Roof Slope Defined

Pitch angle incline slope they all can be used to refer to the steepness of a roof.

Roof slope defined. Roof slopes are most commonly defined by the rise over run ratio. Slope is the incline of the roof expressed as a ratio of the vertical rise to the horizontal run where the run is some portion of the span. Definition of roof slope. If a roof slope rises say 4 inches when measured 12 inches along the bottom of a horizontal roof truss the roof slope is said to be 4 12.

Roof pitch defined and explained pitch is the term used to describe the angle slope or slant of your roof. Low slope roofs are from 0 to 3 12 in pitch. This ratio is always expressed as inches per foot. Roof pitch designations are comprised of two numbers indicating a ratio.

In the roofing trade the go to term is pitch and it is expressed in terms of 12 inches so the pitch of a roof is determined by how many inches the slope rises for every 12 inches it runs horizontally. The pitch of a roof is its vertical rise over its horizontal span. 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. Some sources consider low slope to include 3 12 pitch roofs.

Roof slope is the amount of vertical change in height as a ratio of horizontal distance traveled also expressed as inches of rise per foot of horizontal run or cm of rise per m of horizontal run. See low slope roofing. The ratio can be indicated by a division slash separating the numbers such as 2 12 or 7 12. If asphalt shingles are to be installed on a low slope roof special steps are required to avoid short roof life and roof leaks.

However most often a ratio of pitch also fraction is slang used for the more useful slope of rise over run of just one side half the span of a dual pitched roof. I e 4 inches of rise per 12 inches one foot of run. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.