For roof slopes expressed as x in 12 rise in run the roof pitch multiplier is determined by finding the square root of rise run 1.
Formula roof pitch multiplier.
See the image below for more explanation on rise run and pitch.
So in this case for every 12 inches the roof goes across horizontally b while rising 6 inches a there s actually 13 416 inches of roof c.
A 2 b 2 c 2 where a is the rise of the roof b is the run of the roof and c is the rafter hypotenuse of the triangle with side lengths a and b.
The maths behind this number is that it is the square root of rise run 2 1.
The formula for the roof pitch multiplier comes from the famous pythagorean theorem.
Multiply 20 and 40 which equals 800.
Use our roof pitch calculator to find the pitch of your roof.
Now solving for c in the equation above gives.
Multiply step 1 and step 2 i e.
The roof pitch is important in determining the appropriate installation method and how much roofing material will be needed.
Next multiply the footprint of the roof by the multiplier below for your roof pitch to find the overall roof area.
A roof pitch multiplier also known as a roof pitch factor is a number that when multiplied by the area covered by a sloped roof gives the actual area of the roof.
Although there s isn t any standard pitch of a roof used on all kinds of sloped roofs you can determine the range of pitches by using a roof angle calculator and by considering factors like the local climate and roofing materials.
Image 1 12 to 12 12 roof pitch 7 12 pitch.
A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally.
For example a 4 12 pitch roof that is 100 square feet.
100 1 054 105 4ft2.
Roof pitch is used to describe the slope or angle of the roof.
If the home measures 20 x 40 and has a 7 12 roof then to calculate the slope of the roof follow these steps.
Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio.
A 12 in 12 pitch is a steep 45 degree angle roof.
Roof pitch or slope is a measure of vertical rise to horizontal run expressed in inches per foot.
800 multiplied by 1 16.
Once you know the roof slope multiplier for a particular slope you can use it to find the actual area of any size sloped roof with the same slope.
Find the value of 7 12 from the roof slope multiplier table which is 1 16.
Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs.
