Roof Pitch Angle Table

Often you express roof pitch as the ratio between the rise and the run in the form of x 12.

Roof pitch angle table.

Low slope roofs are from 0 to 3 12 in pitch. Some sources consider low slope to include 3 12 pitch roofs. Other than the 45 roof slope which is 12 in 12 none of the standard roof pitches 5 in 12 6 in 12 etc are equal to a whole degree. For example if the roof pitch is 45 then sec 45 1 414213.

Rise run rise run slope. That s your roof pitch multiplier. This means if a roof rises 4 in the length of 12 your roof pitch would be 4 12 or 18 43 degrees. The roof pitch calculator calculates slope pitch angle and rafter lengths based on input of rise m and run r.

First convert the pitch to a slope. For help converting any slope from one way of expressing it to another see roof slope expressed as rise. To find the angle of a roof in degrees convert the pitch to a slope then convert to degrees by finding the arc tangent of the slope. 45 this is our pitch calculator which will convert pitch to angle or angle to pitch for half degree roof slope calculations.

Notes to the table above. Find the inverse tangent of the pitch to find the angle in degrees. Enter any angle or fraction of angle to find pitch. If asphalt shingles are to be installed on a low slope roof special steps are required to avoid short roof life and roof leaks.

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. On blue prints architects engineers usually display the pitch of a roof in the format shown on the image where number 4 represents a rise and number 12 represents a length. Usually they come in the form of a roof pitch diagram chart but other times it will be presented to you in a conversion format. Enter any pitch or fraction of pitch to find angle.

A 12 12 pitch roof has a pitch angle of 45. To do this simply convert the rise and run as a fraction to a decimal form eg. Run degrees and percentage. To convert between american roofing ratios and pitch degrees follow these steps.

Divide the first part of the ratio by 12 to work out the pitch. Roof pitch degree table. Two most common methods 4 12 or 4 12 are used for marking the pitch of a roof. If you know the roof pitch in degrees find the secant of the slope using a scientific calculator.

Use the diagrams on this page as a reference when inputting rise and run and while interpreting the calculated results.