Take the roof s total square footage and divide by 32.
Roof sheathing square footage.
Steep roofs measure your house at ground level then add in the roof s overhang for greater accuracy.
According to the united states census the average roof is 17 squares or about 1 700 square feet.
The calculator cannot account for complex shapes based on a measurement of square footage alone.
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 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.
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.
A 4 8 sheet of plywood is 32 ft 2.
If you are calculating the number of sheets needed for a hip roof then for the value of the gable overhang use the eaves overhang dimension assuming it is the same all around.
Divide the total roof area by 32 to get the number of sheets you will need to cover the roof.
A typical 4 foot by 8 foot sheet of plywood covers 32 square feet.
This will give you the total number of sheets to buy.
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.
Cecil venturella march 3.
Divide the rise by the run the run is 12.
If your roof has triangles and other shapes you ll need to use a calculator to find the square footage.
Roofing cost per square foot.
Once you have the area you can divide by the area of a sheet of plywood to find the number of sheets needed.
1square of roofing covers 100 square feet of roof a bundle is 1 3 of a square.
Net free ventilation area may be reduced to a minimum of 480 square inches for each 1 000 square feet 1 300th when certain building code provisions are met see section r806 2 of the 2012 international residential code or section 1203 2 of the 2012 international building code for more details.
When calculating roofing costs per square asphalt shingles run from 350 and 500 per square metal or tin roofs costs 600 to 1 200 per square and concrete or clay costs between 1 200 and 1 800 per square.
Get the square footage of roof and divide it by 100 and it will give the number of squares you need and for every decimal number over 3 buy a bundle to achieve the amount of material.
So dividing the area of the roof by 32 will give you the number of sheets needed.
If your roof area is 1 600 square.
