For most home styles roof pitches fall in a range 4 12 a moderate slope up to 8 12 fairly steep.
1 4 roof slope.
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 for every 12 horizontal units the roof must rise a minimum of one fourth vertical unit.
Most roof s have a pitch in the 4 12 to 9 12 range.
Examples of extreme slopes range from 1 4 12 almost flat to 12 12 sloping down at a perfect 45 degree angle.
3 of rise per 12 of run is the same as 1 of rise per 4 of run or 1 4 25.
Conventional roofs are the easiest to construct and you can walk on them safely.
While roof slope is typically expressed in rise it can also be expressed in degrees or in percent of slope.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
Why is the roof slope 25.
Conventional from 4 12 1 in 3 to 9 12 3 in 4.
The table below shows common roof pitches and the equivalent grade degrees and radians for each.
That s the same as a 14 degree slope or a 25 slope.
High pitched roofs often need extra fasteners and their pitch can be as high as 21 12.
You can also calculate roof pitch even without using a roof slope calculator.
Slope ratio a roof that rises 4 inches for every 1 foot or 12 inches of run is said to have a 4 in 12 slope.
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.
A 3 in 12 roof rises 3 for every 12 of run.
They have a pitch ranging from 4 12 to 9 12.
A 4 12 is a roof slope that rises by 4 inches for every 12 inches across.
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.
This means that the rise of the slope goes up or down 8 inches for every 12 inches.
These roofs have a pitch less than 4 12.
Liquid applied roofing must have a design roof slope of 1 4 12 or greater 2 slope.
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.
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.
An example for a steep sloped roof is 8 12.