Roof Pitch Ratio Definition

Notes to the table above.

Roof pitch ratio definition.

Roof pitch refers to the slope which the rafter creates. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. A roof that rises 4 inches for every 1 foot or 12 inches of run is said to have a 4 in 12 slope. 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.

Sometimes pitch is also expressed in fraction form using a fraction. Low slope roofs are from 0 to 3 12 in pitch. Roof pitch is used to describe the slope or angle of the roof. This is the slope of geometry stairways and other construction disciplines or the trigonometric arctangent function of its decimal.

Some sources consider low slope to include 3 12 pitch roofs. The pitch of a roof is its vertical rise over its horizontal span. Often you express roof pitch as the ratio between the rise and the run in the form of x 12. The slope ratio represents a certain amount of vertical rise for every 12 inches of horizontal run.

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. You can assess this in two ways either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof. Pitch is thus the ratio of the rise in inches to a 12 inch run and is often expressed using a semicolon for example 6 12.