Roof Area Multiplier

Depending whether the roof area is measured horizontally possibly from a drawing or photograph a correction factor is necessary to determine the actual area of the roof.

Roof area multiplier.

Take your area result and multiply it by the pitch multiplier or slope correction factor found in the table above to arrive at the roof s surface area. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally. The maths behind this number is that it is the square root of rise run 2 1. Or just enter your numbers into this roof pitch degrees.

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. Use our roof pitch calculator to find the pitch of your roof. This makes measuring easier knowing that you are able to get the exact measurement of roofs by merely standing on the ground. The roof pitch multiplier is responsible for giving an accurate pitch measurement of the roof.

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. 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. Next multiply the footprint of the roof by the multiplier below for your roof pitch to find the overall roof area. And for a roof with a slope of 6 12 that number 1 118 is your roof slope multiplier.

Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs. Determine how many square feet of roof area a building has by measuring blueprints or plans. Simply multiply this number by the area covered by a sloped roof to obtain the total surface area of the roof itself. 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. The pitch of the roof is the rise over a 12 inch run. For example a 4 12 pitch roof that is 100 square feet. Determine how many square feet of roof area a building has by measuring from the ground.

Now you re ready to price out the materials. And that s the number you were looking for. That gives you 5 590 square feet which is the actual area of the surface of the roof. Given pitch and a horizontal area measurement multiply the horizontal area by a correction factor corresponding to pitch provided in the table below to determine the actual area of the roof to be used in the roofing material calculator.