Roof Pitch Multiplier

A flat roof has a pitch of 1 meaning the material needed is 1 times the size of the roof.

Roof pitch multiplier.

The pitch of this roof is 4 8 12. Determine how many square feet of roof area a building has by measuring from the ground. 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. Now divide the rise by the multiplier to get the pitch eg.

After safely measuring your roof to discover the pitch you can use the graph below to calculate your roof pitch in degrees and multiplier. 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. Take the area of the roof s footprint say it s 5 000 square feet and multiply 5 000 by 1 118. 48 10 4 8.

This makes measuring easier knowing that you are able to get the exact measurement of roofs by merely standing on the ground. 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. The roof pitch multiplier is responsible for giving an accurate pitch measurement of the roof. Roof pitch multiplier c over b.

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. The chart gives a number of roof pitch multipliers for different roof slopes. 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.

Based on the pitch you can use the multiplier to determine the amount of material needed for a roofing project. And for a roof with a slope of 6 12 that number 1 118 is your roof slope multiplier. Determine how many square feet of roof area a building has by measuring blueprints or plans. The maths behind this number is that it is the square root of rise run 2 1.