Plywood Thickness For Metal Roofing

Multi ply is a catchall term for plywood with seven or more plies.

Plywood thickness for metal roofing.

Manufacturers express the thickness of metal panels as their gauge with 22 gauge being the thickest and 29 gauge the thinnest of traditionally sold metal roof and wall panels. Nearly all homes have a layer of plywood or. Foot and with a maximum of spacing of 16 inches between rafters. To secure it measure it roll it out over the plywood cut it to the dimensions of the roof with a roofing or utility knife and finally hammer it securely to the plywood with 1 2 inch roofing nails.

He said it s only a difference of 1 8 thickness. On top of this underlayment goes a slip which protects the material from tearing as the metal roof expands and contracts with changing weather. Plywood typically comes in 4 8 ft. I thought perhaps he made a mistake but no this is what he is proposing.

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. 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. Sheet with varying thickness. This kind of plywood can be used on roofs with minimal load.

If you ensure the plywood is in good condition and well protected before placing the metal roofing you can expect the average life expectancy of your metal on plywood roof to be 40 70 years. A half inch thickness is considered to be standard in a lot of areas and it should work just fine considering that it s deemed okay by the roofing contractor after considering the things above. Steeper rather than flatter roofs will have lesser load per sq. The existing plywood on my roof is only 3 8.

Selecting metal roofing trim. Metal roofing panels rated for architectural use attached to purlins horizontal pieces of wood or metal fastened to roofing trusses are structurally sound when installed according to your roofing manufacturer s instructions and local building codes. It s the standard for spacing of 24 inches in the rafter although as mentioned a 5 8 inch thick is more ideal. This plywood is strong and durable enough for use in roofing framing and other exterior structural projects.

The minimum thickness of plywood used for roofing is 3 8 th of an inch. If you are installing metal roofing onto plywood it is even more imperative that you have a solid base to place the metal roofing on. For many applications a layer of plywood underneath your metal roofing is an unnecessary expense. A local roofer submitted a proposal to me for a roof placement that included replacing rotten plywood with 1 2 cdx.