Roof Slope In Percentage
The following table shows how the same common roof slopes can be expressed using rise in run.
Roof slope in percentage. Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio. A pitch over 9 12 is considered a. Some sources consider low slope to include 3 12 pitch roofs. Low slope roofs are from 0 to 3 12 in pitch.
Metal roof shingles can only be installed on roof slopes of 3 12 or greater 25 slope. If asphalt shingles are to be installed on a low slope roof special steps are required to avoid short roof life and roof leaks. A low slope roof is anywhere from 2 in 12 to 4 in 12. See low slope roofing.
Rise run pitch use this when you express the pitch in percent pitch tan angle use this when you express the angle of the roof pitch in degrees what is the standard pitch of a roof. Finally you can find the roof pitch in the form of x 12. Angle percentage 6 10 x 100. Conventional slope roof range between 4 in 12 and 8 in 12.
Slopes greater than 18 12 are found on a frame roofs and some mansard style. A flat roof has a slope of 2 in 12 or less. Calculated out this gives an angle percentage of 60. Most roof s have a pitch in the 4 12 to 9 12 range.
Pitch rise run 1 5 6 25. Angle arctan pitch arctan 0 25 14. The run always remains constant at 12 inches. Slope percent amount of rise amount of run x 100.
Rafter rise run 1 5 6 2 25 36 38 25rafter 38 25 6 18 m. Recalculate this value into an angle. This means for every 12 horizontal units the roof must rise a minimum of 3 vertical units. Calculate the roof pitch as the proportion of rise and run.