Formula For Roofing Area

Divide your roof pitch by 12.

Formula for roofing area.

Roof pitch is given as the number of inches in height change over the distance of one foot. Calculating an area of a triangle when estimating a roof. Divide the area you calculated in step 4 by 100. In the construction industry roofs are measured in squares one square equals 100 square feet.

If your number is 1 3 squared would yield 1 9 after that add 1 to your number. Dividing by 12 gives the ratio of inches in rise per distance. So if you divide your answer of a product of length times height by two you will get the area of a triangle. The answer to this is the total number of squares on your roof for which you need to purchase shingles.

Next square your result. 1 9 1. The length l times the height h of a triangle is twice its area a2.