Only use CDX plywood for the interior of a house, where water damage is far less likely. Do not use CDX for roofing, sheds, or other places that are exposed to moisture consistently. The sole exception to this is pressure treated CDX, which can survive for decades without even a protective coating.
What is CDX plywood used for?
CDX Plywood is used primarily by contractors to build exterior walls and roofs. CDX plywood has one side veneer grade “C” and one side veneer grade “D”. The two are bonded together with glue which can withstand a little moisture.
What is the best type of plywood for roofing?
Builders love plywood for its water resistance, structural stability and low cost. They also love oriented strand board, though. It costs even less and is comparable to plywood on the other two counts, and they increasingly prefer OSB for roof sheathing. Either is an acceptable choice in most jurisdictions.
What grade of plywood is used for roof sheathing?
1/2 or 3/4-inch Plywood for Roof Sheathing? – Traditionally, 1/2-in CDX plywood was common choice with 24-in rafter spacing. However, heavier roof loads may require the use of 3/4-in CDX plywood for roof sheathing. Roofs with less pitch often carry heavier loads, including snow and ice accumulations in the winter.
What is the best roof sheathing?
OSB is now the most-used sheathing and subflooring material for new roofs and roof replacements. OSB is currently selling for less than plywood by approximately $3 per sheet, meaning a savings of several hundred dollars per conventional home.
Why is CDX plywood so expensive?
CDX is a type of plywood. Basically, plywoods are thin veneer sheets that are glued and held together with linking plies. … The less the number of knots, holes and repaired defects the more expensive the plywood. If so, it therefore, means CDX has the most number of knots and defects, making it a lower grade plywood.
Which is better OSB or CDX plywood?
CDX and OSB are used for almost similar things, but because they have different features, one is better applied in some tasks and the other one on other tasks. CDX is best for sub-flooring. … OSB also seems to be good for roof sheathing. But take care, it also requires that you use water-resistant coating at the edges.
How much is a sheet of plywood for roofing?
Your price could vary depending on how much the roofing company charges for labor, but generally, you can expect to spend between $70 to $100 for each sheet of plywood. A 4 x 8 sheet of plywood covers about 32 square feet of roof area—and the average roof measures about 3,000 square feet.
Do you use treated plywood for roofs?
Contractors generally recommend treated plywood rather than regular plywood for roof decking because condensation can build up on the sheathing and cause rot. Roofers understand that when it comes to the roof deck, the amount of water that gets on the wood is a concern.
Can you put plywood over plywood on roof?
The new plywood will have to be nailed to the rafters or roof trusses. … But, with the old plywood left in place, it will be considerably more difficult to locate the rafters to ensure proper nail placement.
Is 7/16 OSB OK for roofing?
…or a non-laminated panel, such as this OSB. Either one is acceptable. The typical thickness of roof sheathing is about 7/16-inch, which is just under 1/2-inch. … If you find 3/8-inch plywood installed as roof sheathing, it’s a good idea to make your client aware of its presence.
What is the best thickness for roof sheathing?
The recommended thickness for roof sheathing is ⅝” thick. Sheathing with a thickness of less than that is much more likely to result in bowing between framing which could potentially compromise your exterior roof material.
Is OSB stronger than plywood?
Wood fiber is used more efficiently in osb. Osb is stronger than plywood in shear. Shear values, through its thickness, are about 2 times greater than plywood.
Should plywood go under metal roof?
For many applications, a layer of plywood underneath your metal roofing is an unnecessary expense. … Boards measuring 1 inches by 4 inches or 2 inches by 4 inches are commonly used for purlins, though never use treated lumber because it will corrode the steel roof and fasteners.