How To Figure Roofing Area

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.

How to figure roofing area.

If the house has an irregular shape measure each part separately figure the separate areas and add them together. This applies to lengths as well as areas. To calculate the area of your roof first you ll need to calculate the pitch of it. That gives you 5 590 square feet which is the actual area of the surface of the roof.

The pitch of the roof is the rise over a 12 inch run. Both metric and imperial measurement systems are displayed in a popup menu over the results area. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally. To accurately calculate the area of your roof you must first determine its slope or pitch.

1 roof square 100 square feet. 100 1 054 105 4ft 2. 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. 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.

The length l times the height h of a triangle is twice its area a2. So if you divide your answer of a product of length times height by two you will get the area of a triangle. While it is possible to estimate the amount of necessary materials using only the. Use our roof pitch calculator to find the pitch of your roof.

And that s the number you were looking for. Next multiply the footprint of the roof by the multiplier below for your roof pitch to find the overall roof area. Multiply the length by the width to arrive at the ground area of the house. For example a 4 12 pitch roof that is 100 square feet.

First use your measuring tape to measure 12 inches on your large level and make a mark at the 12 inch line. Climb to the top of your roof. Take the area of the roof s footprint say it s 5 000 square feet and multiply 5 000 by 1 118. L 30 feet h 12 feet 30 12 2 180 square feet.

Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs.