Express roof pitch as the ratio of the amount of the vertical rise of a roof or rise over the corresponding horizontal distance or run you write the pitch assuming a run of 12 inches thus the ratio would describe how much a roof rises for each foot of the run.
Standard angle of roof.
Pitches above 9 12 are very highly angled and are designated steep slope roofs.
Locate its tangent or tan and follow the left row for you to read its corresponding degree.
A roof slope of 7 12 is also good and can provide the additional benefit of helping minimize the effects of wind driven rain.
First convert the pitch to a slope.
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.
Divide its rise by run in.
As aforementioned there is no standard pitch of a roof.
5 round the calculated value to the nearest whole degree.
The most commonly used roof pitches fall in a range between 4 12 and 9 12.
Greek says one must keep rafter length in range of 1 9 to 1 7 th of span but as per roman style the standard dimensions are kept about 1 3 to 2 9 th of span with an angle of 23 to 24 degree.
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.
Roof pitch and corresponding angles.
The a frame style roof shown just above located on highway 61 just south of hovland minnesota is built at a 75 angle and is considered a very steep roof.
To conclude the example the.
The table below describes different roof slopes giving roor slope in rise run in inches and re expressing the same slopes as angle grade walk ability and roof type or class.
Rise run rise run slope.
This means if a roof rises 4 in the length of 12 your roof pitch would be 4 12 or 18 43 degrees.
Determine its angle through taking a 12 inch level and.
Identify the rise and run.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
Roof slopes between 4 12 and 6 12 are best for minimizing the wind uplift effects in high wind zones.
To do this simply convert the rise and run as a fraction to a decimal form eg.
Pitches lower than 4 12 have a slight angle and they are defined as low slope roofs.
Usually average roof pitch is determined using the same roof length method.
For example the arc tangent of 0 5 is 26 57 so the roof angle or angle of the slope is 26 57 degrees.
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.