Slope Of A Roof Pitch

Most roof s have a pitch in the 4 12 to 9 12 range.

Slope of a roof pitch.

Squaring building lines example 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. Locate the level s 12 inch mark. Use a level against the underside of the rafter you re measuring to get the most accurate value. The run is the measurement from the outside of one wall s top plate to a point directly below the center of the ridge picture a right triangle.

How do you calculate the slope of a roof. A roof that rises 4 inches for every 1 foot or 12 inches of run is said to have a 4 in 12 slope. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. The slope is the measurement of the rise of the roof to the run of the roof and is expressed as inches per foot in a ratio format.

This ratio is always expressed as inches per foot. A pitch over 9 12 is considered a steep slope roof between 2 12 and 4 12 is considered a low slope roof and less than 2 12 is considered a flat roof. The table below shows common roof pitches and the equivalent grade degrees and radians for each.