Roof Pitch Conversion Factor

To obtain an accurate roof pitch measurement properly measure the rise and run.

Roof pitch conversion factor.

The roof slope factor chart also consists of conversion factors to determine the slope of the roof. Using a tape measure make a pencil mark 12 inches from the end of a carpenter s level. 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. 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.

The roof pitch is important in determining the appropriate installation method and how much roofing material will be needed. Usually they come in the form of a roof pitch diagram chart but other times it will be presented to you in a conversion format. A 10 slope roof should not be confused with a 10 pitch roof as a 10 slope roof means that the roof rises by ten inches for every foot of run. 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.

In essence a roof pitch chart is provided as a rough guide usually by a roofing company to help you see what the average roof pitches tend to be. Then you ll be able to measure slope from an unfinished attic space under the roof. Two most common methods 4 12 or 4 12 are used for marking the pitch of a roof. The combination of two numbers are used to display or show the roof pitch.