Roof Slope Ratio Chart

This is very useful information for many purposes especially for roof framing the slope sometimes called pitch is calibrated on speed squares.

Roof slope ratio chart.

Low slope roofs are from 0 to 3 12 in 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. Pitch rise run 1 5 6 25. Some sources consider low slope to include 3 12 pitch roofs.

Calculate the rafter length substituting these values into the following formula. A ratio of 1 1 62 is known as the golden ratio and therefore the vast majority of roof pitch in degrees charts you see will be working to this ratio at the very least. Rafter rise run 1 5 6 2 25 36 38 25rafter 38 25 6 18 m. Download the slope chart pdf.

Notes to the table above. Calculate the roof pitch as the proportion of rise and run. Valley hip factor. Although there s isn t any standard pitch of a roof used on all kinds of sloped roofs you can determine the range of pitches by using a roof angle calculator and by considering factors like the local climate and roofing materials.

Let s say it is equal to 1 5 m. Once you ve figured out the pitch of your roof you can consult the following chart to discover the slope factor and hip valley factor.