Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter.
1 8 roof factor.
8 1 x 12 scale factor 96.
1 20 multiply the feet by 12.
A roof that rises 8 feet over a 24 foot span was said to have a 1 to 3 pitch.
1 8 1 0 invert the fraction and multiply by 12.
Then multiply the square footage with the roof pitch factor to get the total area of the roof.
That is if your tape reads 7 then add 1 that will give you 8 12.
This will give you the rise over run or pitch.
A 10 slope roof should not be confused with a 10 pitch roof as a 10 slope roof means that the roof rises by ten inches for every foot of run.
The pitch fraction represents a certain amount of vertical rise over the entire span.
Select the desired scale.
The maths behind this number is that it is the square root of rise run 2 1.
The pitch of this roof is 4 8 12.
If the rise is 4 feet over a 24 foot span then the roof pitch was said to be 1 to 6 the pitch can be expressed numerically as a fraction.
Set the level on the edge of the speed square as shown below then place the heel of the speed square on a rafter or gable edge of the roof.
Measure with a speed square.
For example if you measure 4 inches the pitch of your roof is 4 12.
A roof pitch multiplier also called a roof pitch factor is a number that is multiplied by the area covered by a sloped roof to produce the area of the actual surface of the roof.
For example the roof layer that protrudes above the roof is 1 so add 1 to your tape reading.
Image 1 12 to 12 12 roof pitch 7 12 pitch.
To convert an engineering drawing scale to a scale factor.
Roof pitch degree table.
A speed square and level can be used to easily find the pitch of a roof.
For example given a roof with.
To convert an architectural drawing scale to a scale factor.
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.
20 x 12 scale factor 240.
The calculator above can handle much of this math.
Valley hip factor.
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.