How To Figure Plywood For A Roof

To find the amount of plywood needed to cover a roof start by finding the area of the roof.

How to figure plywood for a roof.

Multiply the length of the roof in feet by the width of the roof in feet to find the area of the roof in square feet. Add 20 percent to that figure to allow for the roof slope which results in 1 320 square feet of roof area. This will give you the total number of sheets to buy. Solving for the number of sheets of plywood necessary for more complicated shapes requires at least some estimating.

Once the area is known divide by the area of a 4 8 sheet to find how much sheathing is needed. The calculation is based on 4 x 8 sheets 32 square feet each. This basically calculates the number of sheets needed for a gable roof. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally.

Things you will need. A 12 in 12 pitch is a. Find the area of a roof. One sheet 32 ft.

The square footage of a hip roof area is identical to the square footage of a gable roof of the same measurements. For example if your roof is 3 000 square feet divide 3 000. Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs. To accurately calculate the area of your roof you must first determine its slope or pitch.

For a shape like a triangle gables and hips trapezoid hip side with the ridge or trapezium gable roof with a valley. You should be prepared to have about 15 percent waste so multiply your figure by 1 15. Calculate how many sheets of plywood are needed. Follow theses guidelines for a closer estimation.

For example if the area to be covered in plywood is 800 ft 2 then 25 sheets of plywood will be needed to cover it. Divide the roof s area by 32 32 is the total area of one sheet of plywood to find this figure. Find the average length by measuring at the center of. One 4 by 8 foot sheet of osb or plywood is 32 square feet.

The calculation is based on that the plywood or osb oriented strand board sheets are of a 4 x 8 size. If you know you ll be using 4 foot by 8 foot sheets of plywood use the total roof area to find the set number of sheets you ll need. Take the roof s total square footage and divide by 32. Roof sheathing hip roof imperial calculator estimate the number of sheets of plywood or osb that are needed for sheathing a hip roof.

Divide 1 320 by 32 to get 41 plywood sheets.