Step 1 multiply 20 and 40 which equals 800.
Roof pitch factor multiplier.
2280 1900 380 feet added for pitch.
The roof slope factor chart also consists of conversion factors to determine the slope of the roof.
And for a roof with a slope of 6 12 that number 1 118 is your roof slope multiplier.
This will give you the rise over run or pitch.
Step 2 find the value of 7 12 from the roof slope multiplier table which is 1 16.
It is sometimes called the roof pitch multiplier.
This roof pitch chart will give you your multiplier.
So the actual roof surface if it were laid down flat on the ground would be 1 118 times larger than the footprint of the roof.
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.
For example if you measure 4 inches the pitch of your roof is 4 12.
If the home measures 20 x 40 and has a 7 12 roof then to calculate the slope of the roof follow these steps.
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.
The headache of using pythagoras and trigonometry can be spared by making use of these charts.
If you know the pitch of a roof you can use the numbers in the following pitch table to do the following.
Take the area of the roof s footprint say it s 5 000 square feet and multiply 5 000 by 1 118.
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 roof pitch conversion factor is a number that when multiplied by the area covered by the roof gives an estimate the total surface area of the sloped roof itself.
That gives you 5 590 square feet which is the actual area of the surface of the roof.
