Roof Pitch Conversion Factor

It is sometimes called the roof pitch multiplier.

Roof pitch conversion factor.

The roof pitch conversion factor is a number that when multiplied by the area covered by the roof gives an estimate the total surface area of the sloped roof itself. This means if a roof rises 4 in the length of 12 your roof pitch would be 4 12 or 18 43 degrees. Roof pitch refers to the slope which the rafter creates. In essence a roof pitch chart is provided as a rough guide usually by a roofing company.

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