If a roof rises 1 in a length of 12 this is 1 12 roof pitch.
Roof slope 1 4 over 12.
This means if a roof rises 4 in the length of 12 your roof pitch would be 4 12 or 18 43 degrees.
This forms an angle of 18 5 between the horizontal section and the roof and creates a gentle incline that is seen as a midpoint between a low pitch and medium pitch roof.
A roof that rises 4 inches for every 1 foot or 12 inches of run is said to have a 4 in 12 slope.
Examples of extreme slopes range from 1 4 12 almost flat to 12 12 sloping down at a perfect 45 degree angle.
A pitch over 9 12 is considered a steep slope roof between 2 12 and 4 12 is considered a low slope roof and less than 2 12 is considered a flat roof.
The table below shows common roof pitches and the equivalent grade degrees and radians for each.
For every 12 horizontal feet the roof changes 8 feet in vertical height.
Roof pitch degree table.
High and low pitch examples.
Low pitched roofs are generally difficult to maintain and you need special materials to prevent leaks.
Most roof s have a pitch in the 4 12 to 9 12 range.
This will give you the rise over run or pitch.
A 4 12 is a roof slope that rises by 4 inches for every 12 inches across.
The slope ratio represents a certain amount of vertical rise for every 12 inches of horizontal run.
Image 1 12 to 12 12 roof pitch 7 12 pitch.
Slope conversion tables 1 4 1 2 3 4 1 1 1 4 1 1 2 1 3 4 2 2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 0 25 0 50 0 75 1 00 1 25 1 50 1 75 2 00 2 25 3 4 5 6 7 8 9 10.
For example if you measure 4 inches the pitch of your roof is 4 12.
They have a pitch ranging from 4 12 to 9 12.
If the rise is 6 inches for every 12 inches of run then the roof slope is 6 in 12 the slope can be expressed numerically as a ratio.
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 most home styles roof pitches fall in a range 4 12 a moderate slope up to 8 12 fairly steep.
Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter.
These roofs have a pitch less than 4 12.