In essence a roof pitch chart is provided as a rough guide usually by a roofing company.
Roof pitch conversion factor.
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.
Roof pitch refers to the slope which the rafter creates.
A roof pitch multiplier also called a roof pitch factor is a number that is multiplied by the area covered by a sloped roof to produce the area of the actual surface of the roof.
Roof pitch and corresponding angles.
It is sometimes called the 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 slope factor chart also consists of conversion factors to determine the slope.
For roof slopes expressed as x in 12 rise in run the roof pitch multiplier is determined by finding the square root of rise run 1.