The table below shows common roof pitches and the equivalent grade degrees and radians for each.
For roof slopes from 2 12 to 4 12.
Roof pitch is a term describing how steep or flat your roof slope is.
For example if you measure 4 inches the pitch of your roof is 4 12.
For a slope of 35 tan 35 0 700.
Most roof s have a pitch in the 4 12 to 9 12 range.
Divide the percentage number by 100.
Two most common methods 4 12 or 4 12 are used for marking the pitch of a roof.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
I e 4 inches of rise per 12 inches one foot of run.
For a slope of 55 55 divided by 100 0 55.
Giving you a slope of 8 4 in 12 or.
55 slope is equal to a slope of 28 81.
If this isn t practical then perform the same measurement on the underside of.
Find the arctangent of the resulting value.
If a roof slope rises say 4 inches when measured 12 inches along the bottom of a horizontal roof truss the roof slope is said to be 4 12.
Roof slopes are most commonly defined by the rise over run ratio.
This will give you the rise over run or pitch.
The combination of two numbers are used to display or show the roof pitch.
8 2 5 inches in 12.
Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter.