This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
Slope of a roof in degrees.
S angle tan 1 1 m 2 m 26 6 slope expressed as grade.
Sometimes slope is referred to as pitch angle rise incline or grade.
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.
Other than the 45 roof slope which is 12 in 12 none of the standard roof pitches 5 in 12 6 in 12 etc are equal to a whole degree.
To find the angle of a roof in degrees convert the pitch to a slope then convert to degrees by finding the arc tangent of the slope.
To see what the degree equivalents are for standard rise in run roof pitches see our page quick reference.
Slope as angle for an elevation of 1 m over a distance of 2 m can be calculated as.
First convert the pitch to a slope.
S angle angle rad degrees x horizontal run m ft y vertical rise m ft example slope as angle.
Locate its tangent or tan and follow the left row for you to read its corresponding degree.
Calculated out this gives an angle of 23 27 degrees.
Use a level against the underside of the rafter you re measuring to get the most accurate value.
Locate the level s 12 inch mark.
The following table shows the roof pitch rise in run equivalents for all roof slopes in degrees from 1 to 72.
Rise run rise run slope.
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.
How do you calculate the slope of a roof.
A 6 rise in a 12 inch run.
The minimum roof pitch for shedding snow is around 30 or a 6 12 or 7 12 slope although this is not a definite as the material of your roof the direction of the snow and wind are some factors that can affect whether or not snow will slide as roofs of as little as 10 have been reported to shed snow.
Determine its angle through taking a 12 inch level and.
Divide its rise by run in.
With a 12 in 12 slope the wall or roof rises 12 inches in a 12 inch run a 12 in 12 slope 45 one could be inclined to assume that a 6 in 12 slope would equal half of that 22 5.
To do this simply convert the rise and run as a fraction to a decimal form eg.
The most precise way to find the roof s slope is by measuring it from the underside.
Access one of the rafters then take.
Slope expressed as angle.
Roof slope expressed as rise.
Many different professions use slope in describing an angle.
For example in construction you may refer to the pitch of a roof or the grade of a slab.
