If you don t want to do a lot of measuring you can use your pitch calculation to get an estimated square footage of your roof.
How to find roof square.
The length l times the height h of a triangle is twice its area a2.
How to estimate roofing materials.
For square or rectangular roofs you ll only need to record the length and width.
Extend your tape measure along the outer edges of the roof to find its length and width in feet.
Measure the ground dimensions of the house using a tape measure and write down these dimensions.
This is simply 100 square feet of roof.
Because each 100 square feet of roof is one roofing square divide.
Divide any irregularly shaped areas of the roof into more manageable triangles and rectangles then calculate square footage for those individual elements and add them to get the total square footage.
For example take an area made up of a triangle that s 20 feet high and has a base of 40 feet plus a square that s 40 feet by 40 feet.
To find the squares divide the overall roof area by 100 and then round up.
Once you have your roof s pitch divide the number by 12.
Convert the area to roofing squares.
Keep in mind that the average size of a roof is 1 700 square feet so your total will likely be 10 higher or lower than this figure.
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.
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.
If your number is 1 3.
A square simply refers to a 10 x 10 square of roofing.
So if you divide your answer of a product of length times height by two you will get the area of a triangle.
Measure each side of the main section of the roof.
Although roofing projects are estimated and sold by the square roofing material is often not sold in 1 square increments.
L h 2 area calculating an area of a triangle when estimating a roof.
How do you calculate square footage for a roof.
On a ladder beside the roof place the level a foot or so up the roof hold it level and measure from the 12 inch mark on the level s bottom straight down to the roof.
You will need to express this size in terms of square feet.
Next square your result.
1 roof square 100 square feet.
8 inches and you have an 8 in 12 pitch.
For instance if the roof is 1550 square feet then it is 16 squares.
Pitch measurement method 1.
Multiply the length by the width to arrive at.
