What type of plywood is best for outdoor use?

For exterior projects or projects exposed to weather conditions, you need to use plywood that is suited for those conditions. Your best choices are either ACX or marine grade plywood.

What is an exterior grade plywood?

Exterior plywood is weather (and water) resistant, so it’s strong enough to be used outside and also in areas that are exposed to water and humidity, like a garage. This type of plywood, often made from Douglas fir, is made stronger by adhering its layers with a waterproof glue.

What is the difference between CD and CDX plywood?

CDX sheathing is used primarily by contractors to build exterior walls and roofs. The letters “CD” represent the veneer grades used on the front and back, and “X” means the glue (not the wood) is rated for outdoor exposure—but only for a short time.

Is CDX plywood exterior grade?

CDX plywood is an exterior grade plywood only in the sense of considering the adhesive used for connecting the veneer plys. The wood isn’t pressure treated or treated in any other way to make it waterproof, unless it is marked as being “pressure treated” plywood.

Is exterior plywood the same as marine plywood?

It’s a very common mistake to describe exterior plywood as “marine plywood.” DIY and building shows on television seem to call any plywood “marine plywood.” Over the years “marine” has become a generic term to describe plywood that is exterior rated. Standard exterior plywood is bonded using an exterior phenol glue.

Is CDX plywood rated for outdoor use?

CDX plywood, a stock item at most lumberyards, is a utility grade suitable for most outdoor projects.

Is ACX plywood exterior grade?

ACX is a designation given to a traditional wood exterior plywood panel with one sanded face and one rough face. It can be used in a wide variety of outdoor projects.

Is CDX or OSB better?

Although some people will ultimately choose CDX, many experts argue that OSB is better overall for roofing. OSB is far less likely to expand and contract when exposed to humidity and moisture, even though it will take longer to dry. With wrapping, though, it can withstand the elements without issue.

What is the difference between CDX and RTD plywood?

RTD and CDX plywood are essentially the same exposure 1 graded plywood, except for the superior manufacturing quality of the RTD plywood. This higher quality in the manufacturing process is what makes the RTD plywood a superior product to its CDX predecessor.

Is CDX plywood same as marine grade?

CDX plywood is not marine grade; therefore, it should not be used for the building of boats, although it theoretically could be. The major difference between them is that marine grade plywood is made of more durable veneers, which will withstand exposure to moisture better than CDX plywood.