So keeping with our roof pitch of 4 this gives us 1 9.
Formula to find square footage of a roof.
L h 2 area calculating an area of a triangle when estimating a roof.
1 roof square 100 square feet.
Multiply by the square.
So if you divide your answer of a product of length times height by two you will get the area of a triangle.
A gable roof and a hip roof of the same length and slope will have identical areas.
Add 1 then take the square root.
For example if your roof s pitch is 4 in 12 you would divide 4 by 12.
Adding 1 gives us 1 1 9 10 9 then taking the square root gives us about 1 0541.
Gable or hip roof.
How to calculate square feet of a roof step 1.
Multiply the number of roofing squares for a medium pitch roof by 1 12 to 1 25 or by 1 3 to 1 42 for a high pitch roof to get the square roof area.
1 9 1.
Next square your result.
Multiply the length and width of each square or rectangle shaped plane.
If your roof is flat or has no more than a 3 in 12 pitch you can calculate its total square footage by simply multiplying the length by the width.
Measure the length and width of every roof plane or surface.
Include dormers the small outjuttings over attic.
Calculate each plane separately.
Things you will need steel tape measure.
The length l times the height h of a triangle is twice its area a2.
Steep roofs measure your house at ground level then add in the roof s overhang for greater accuracy.
In cases where a roof has a complex shape such as in the image to the right measuring the dimensions and areas of each part of the roof to calculate total area will result in a more accurate measurement of area.
Calculating the area true once you have your roof s pitch divide the number by 12.