Roof Pitch Numbers

Roof pitch or slope is a measure of vertical rise to horizontal run expressed in inches per foot.

Roof pitch numbers.

The rafter length is 3 4 the span about 48. Pitches above 9 12 are very highly angled and are designated steep slope roofs. A a roof with a 6 rise for every 12 run has a 6 per foot or 6 in 12 pitch. 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. Often you express roof pitch as the ratio between the rise and the run in the form of x 12. 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.

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. Rafter rise run 1 5 6 2 25 36 38 25rafter 38 25 6 18 m. Pitch rise run 1 5 6 25.

Recalculate this value into an angle. Commonly used roof pitches were given names such as greek. So the pitch of a roof is determined by how many inches the slope rises for every 12 inches it runs horizontally. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.

Roof pitch and corresponding angles. Pitches of less than 2 12 are considered flat roofs even though they may be very slightly angled. The angle or pitch of a roof is calculated by the number of inches it rises vertically for every 12 inches it extends horizontally. Pitches lower than 4 12 have a slight angle and they are defined as low slope roofs.

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 7 means that the roof rises 7 for every 12 it runs. 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. For example a roof that rises 6 inches for every 12 inches of horizontal run has a 6 in 12 pitch.

Finally you can find the roof pitch in the form of x 12. The rafters equal the span. 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. 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.

The ridge height is 2 9ths to 1 3 the span an angle of 24 to 34. The ridge height is 1 9 to 1 7th the span an angle of 12 5 to 16.