Roof Pitch Factor Multiplier

Now divide the rise by the multiplier to get the pitch eg.

Roof pitch factor multiplier.

Divide the rise by the run the run is 12. Determine how many square feet of roof area a building has by measuring blueprints or plans. The first thing that you need to understand before picking any selections from a roof pitch multiplier chart is to ensure that it s affordable. If you know the pitch of a roof you can use the numbers in the following pitch table to do the following.

The maths behind this number is that it is the square root of rise run 2 1. Find the square root of the result. 2280 1900 380 feet added for pitch. For any roof slope expressed as x in 12 rise in run the hip and valley factor is determined by finding the square root of rise run 2.

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. For example if you measure 4 inches the pitch of your roof is 4 12. Since pitch is the rise over a 12 inch run divide the run by 12 to get the multiplier in this case 120 12 10. Understanding the roof pitch chart process.

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. That gives you 5 590 square feet which is the actual area of the surface of the roof. Determine how many square feet of roof area a building has by measuring from the ground. Step 1 multiply 20 and 40 which equals 800.

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. The hip and valley factor varies according to the slope of the roof as shown in the table below. This will give you the rise over run or pitch. The calculator above can handle much of this math.

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. It is sometimes called the roof pitch multiplier. If the home measures 20 x 40 and has a 7 12 roof then to calculate the slope of the roof follow these steps. The pitch of this roof is 4 8 12.

48 10 4 8. This roof pitch chart will give you your multiplier. Take the area of the roof s footprint say it s 5 000 square feet and multiply 5 000 by 1 118. And for a roof with a slope of 6 12 that number 1 118 is your roof slope multiplier.

Step 2 find the value of 7 12 from the roof slope multiplier table which is 1 16.