Since this is a flat roof or nearly flat roof.
Roof pitch 1 in 4.
Low slope roofing which requires special materials and techniques to avoid leaks and ranges from 1 12 2 12 to 4 12 1 in 3.
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.
You can go by the measurements taken by walking the roof.
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.
Most roof s have a pitch in the 4 12 to 9 12 range.
Low slope or flat roofs should not be roofed with asphalt shingles because it is much easier for water to infiltrate the roofing material on a roof with a shallow pitch.
Conventional from 4 12 1 in 3 to 9 12 3 in 4.
They have a pitch ranging from 4 12 to 9 12.
These roofs have a pitch less than 4 12.
The table below shows common roof pitches and the equivalent grade degrees and radians for each.
High pitched roofs often need extra fasteners and their pitch can be as high as 21 12.
Low slope roofing needs special techniques and materials in order to avoid leaks and roof damage and it ranges from 1 12 4 12.
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.
You can also calculate roof pitch even without using a roof slope calculator.
0 pitch 1 00x the roof area.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
Asphalt shingles are appropriate on roofs with conventional pitches between 4 12 and 9 12.
The basic ranges of pitch are not uniformly defined but range from flat which are not perfectly flat but sloped to drain water up to 1 2 12 to 2 12 1 in 24 to 1 in 6.
Conventional roofs are the easiest to construct and you can walk on them safely.
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.
1 pitch 1 01 2 pitch 1 02 3 pitch 1 03 4 pitch 1 05 5 pitch 1 085 6 pitch 1 12 7 pitch 1 16 8 pitch 1 21 9 pitch 1 25 10 pitch 1 31 11 pitch 1 36 12 pitch 1 42.
Common rafter elevation if you are calculating rafter length from the center of the ridge beam as shown below you will need to subtract half of the thickness of the ridge beam from the top end of the rafter.
This means if a roof rises 4 in the length of 12 your roof pitch would be 4 12 or 18 43 degrees.
