Roof Pitch Numbers

If a roof increases in height by four inches for every foot of horizontal run it is considered to have a 4 in 12 pitch or just a 4 pitch talk in terms of pitches and you will always be understood in the roofing universe.

Roof pitch numbers.

Angle arctan pitch arctan 0 25 14. Also referred to as roof slope or roof slant so what does the 7 12 in the example to the right mean. The rafters equal the span. Commonly used roof pitches were given names such as greek.

Pitch is thus the ratio of the rise in inches to a 12 inch run and is often expressed using a semicolon for example 6 12. Roof pitch or slope is a measure of vertical rise to horizontal run expressed in inches per foot. The ridge height is 2 9ths to 1 3 the span an angle of 24 to 34. Finally you can find the roof pitch in the form of x 12.

For example a roof that rises 6 inches for every 12 inches of horizontal run has a 6 in 12 pitch. Calculate the roof pitch as the proportion of rise and run. Roof pitch and corresponding angles. The ridge height is 1 9 to 1 7th the span an angle of 12 5 to 16.

This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. This means if a roof rises 4 in the length of 12 your roof pitch would be 4 12 or 18 43 degrees. The rafter length is 3 4 the span about 48. 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.

Recalculate this value into an angle. Roof pitch refers to the slope which the rafter creates. Often you express roof pitch as the ratio between the rise and the run in the form of x 12. So the pitch of a roof is determined by how many inches the slope rises for every 12 inches it runs horizontally.

Pitch rise run 1 5 6 25. 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 angle or pitch of a roof is calculated by the number of inches it rises vertically for every 12 inches it extends horizontally. The most commonly used roof pitches fall in a range between 4 12 and 9 12.

Pitches above 9 12 are very highly angled and are designated steep slope roofs. Pitches of less than 2 12 are considered flat roofs even though they may be very slightly angled. Rafter rise run 1 5 6 2 25 36 38 25rafter 38 25 6 18 m. The 7 means that the roof rises 7 for every 12 it runs.

How to measure roof pitch. The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7.