What Plywood To Use For Roof Decking

Use it indoors or outdoors but avoid using for framing permanent structures such as a shed or a home.

What plywood to use for roof decking.

The minimum thickness of plywood used for roofing is 3 8 th of an inch. Steeper rather than flatter roofs will have lesser load per sq. The common grade of plywood for roof sheathing is cdx. Wood shingle are expensive so when these roofs need to be torn off and replaced it is cheaper to resheath the entire roof and go over it.

Osb and plywood come in thicknesses ranging from 5 16 to 3 4 inch and the thickness needed for a particular roof depends on several factors including rafter spacing expected load and roof design. In addition to the thickness you also need to make sure that you choose plywood that s graded for outdoor use. The sole exception to this is pressure treated cdx which can survive for decades without even a protective coating. Most construction sites will consider the use of either osb or plywood for the roof.

Osb is lightweight relatively inexpensive and strong enough to resist bending or breaking should someone walk on the roof. 5 ply is a versatile type of plywood that is about 4 millimeters thick. Do not use cdx for roofing sheds or other places that are exposed to moisture consistently. Only use cdx plywood for the interior of a house where water damage is far less likely.

As a quick primer in plywood each side is rated from a to d. The industry offers a thickness of anywhere from 5 16 inch to inch. This kind of plywood can be used on roofs with minimal load. Look for something that s graded as exposure 1 or exterior.

This plywood is strong and durable enough for use in roofing framing and other exterior structural. Required dimensions of plywood for roofing. Sheet with varying thickness. In the first half of the 20th century roofs in missouri were built with wood shingles over planks spaced about 1 apart.

Cdx plywood is a construction grade type of plywood that is designed for exposure to the elements. One side is usually better quality than the other c in this case. Foot and with a maximum of spacing of. X stands for exterior use.

It can withstand moisture for a brief period of time but may become warped and delaminated with consistent exposure to the elements. Plank sheathing usually 1 6 or 1 8 was used as a roof deck before plywood. Multi ply is a catchall term for plywood with seven or more plies. It should be placed up on the roof.

Roof sheathing or decking is one of those elements. A is smooth and knot free while d the lowest quality has missing knots and cracks. The thickness of plywood used for roof decking depends on the roof slope the spacing of rafters and the weight of other material to be put over the decking as well as the design load the. In the u s roof sheathing is almost always composed of wood usually osb oriented strand board or plywood.