You can assess this in two ways either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof.
How do you find the angle of a roof pitch.
The 12 inch run is considered standard in roof pitch or angle terminologies.
The traditional method has been rise inches 12 run inches.
Angle the angle of a roof is the same as the roof s slope except instead of being represented as x 12 it is represented in degrees.
This means if a roof rises 4 in the length of 12 your roof pitch would be 4 12 or 18 43 degrees.
Roof pitch is measured in a rise to run ratio with the vertical rise always shown first.
Rise run rise run slope.
If you can t get to your attic you can measure slope on your rooftop as long as it s safe to go up there.
So if your roof is a 45 degree angle that is for every 12 along the horizontal run it rises 12 it s a 12 12 pitch.
Roof pitch refers to the slope which the rafter creates.
To do this simply convert the rise and run as a fraction to a decimal form eg.
After measuring the slope estimate the roof pitch by dividing the slope by 2 if you have a simple gable roof.
The value displayed as the rise will be your x.
The angle of your roof is calculated the same way you d work the angle of a right angled triangle.
Often you express roof pitch as the ratio between the rise and the run in the form of x 12.
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.
If you prefer to work the angle out the traditional way without our handy calculator you can use the following equations to find the length of the rafter and the slope.
Locate its tangent or tan and follow the left row for you to read its corresponding degree.
So use the 12 inch level as a constant run and 18 inch ruler as a variable rise.
Before you calculate roof pitch you ll need to measure the slope of your roof.
This is our pitch calculator which will convert pitch to angle or angle to pitch for half degree roof slope calculations.
Rafter height width from pythagoras remember that at school so.
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.
Total height of building.
First convert the pitch to a slope.
Find all the needed factors in order to determine the pitch angle s degree.
Enter any angle or fraction of angle to find pitch.
The easiest way to do this is by accessing a rafter in your attic if you can.
Enter any pitch or fraction of pitch to find angle.
If it rises only 6 for every 12 it s a 6 12 pitch.
This is useful because sometime you may need to cut a bevel with your circular saw that is not calibrated using roof pitch style this setting on circular saws is calibrated in degrees.