Flat Roof Plywood Sheathing

Before lumber companies began selling osb the standard choice for sheathing a roof with a 24 inch rafter spacing was 1 2 inch cdx plywood the letters cdx indicate that it is construction grade.

Flat roof plywood sheathing.

The typical thickness range for sheathing is 3 8 to 3 4 inch. A is smooth and knot free while d the lowest quality has missing knots and cracks. Zip system roof assembly combines our revolutionary integrated sheathing and flashing tape or liquid flashing to provide a sealed roof for protection against moisture intrusion during construction or if high winds strip the roof covering away. The sheathing is the base you lay over the rafters that holds the roofing felt and shingles.

Up until 2000 plywood held the majority of the market for wall roof and floor sheathing when it was surpassed by osb which as of 2018 held about 75 of the market share. Plywood is typically. If your roof has triangles and other shapes you ll need to use a calculator to find the square footage. It should be placed up on the roof.

A 4 8 sheet of plywood is 32 ft 2. One of the nice things about plywood is the variety of options you can buy. That s considered to be the minimum. Sheathing should be a minimum of 19 32 inch thick.

Once you have the area you can divide by the area of a sheet of plywood to find the number of sheets needed. Follow these 5 simple construction steps for roof sheathing. Never attach roof sheathing with staples. Unlike with plywood siding the plywood sheet to be used for sheathing should be at least 3 8 inch thick.

Plywood is made with an odd number of layers for optimal strength and performance. The common grade of plywood for roof sheathing is cdx. 8d ring shank nails should be used instead. Installing sheathing on a flat roof is much easier than working on a peaked roof.

Plywood is a bit more expensive but is usually stronger and is often selected in cases where the roof covering is heavier such as for slate clay or concrete tile roofs. That s considered to be the minimum. One side is usually better quality than the other c in this case. Odds are that if you pass a housing development of wood framed houses it will have osb oriented strand board as exterior sheathing.

Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame. This minimum will only work if the rafters are set 16 inches apart at most and if the roof doesn t have too much load. As a quick primer in plywood each side is rated from a to d.