Marine grade plywood is essentially the highest-quality plywood you can get. It’s called “Marine grade” in part because it has to be fully capable of standing up to rain, snow, and moisture on a regular, repeated basis in order to qualify. This isn’t the only qualification a piece of plywood needs to meet to be labeled as marine grade, however.
Marine grade plywood can only be made with Western Larch or Douglas Fir wood. It also must have 5 or more layers, with far fewer air pockets and small voids than regular plywood. It can have some knots in the exterior plies, but no knotholes are allowed. It must be bonded with waterproof glue.
Marine grade plywood is made by arranging 5 or more plies of Douglas Fir or Western Larch wood in a perpendicular manner so that the grains are alternating from vertical to horizontal. This perpendicular arrangement of the individual plies is what gives the plywood increased strength.
The plies are bonded together under heat and pressure, using a special type of glue that is waterproof. A water-resistant finish is then added to the exterior. The waterproof glue as well as the lack of voids, knots, and air pockets are the defining features that separate Marine grade plywood from various other types of plywood.
Also, the fact that Marine grade plywood is made with more, thinner layers of high-quality wood as opposed to fewer, thicker layers of lower-quality wood is what sets it apart from other types of plywood.
Marine grade plywood is not to be confused with similar types of plywood like pressure-treated plywood. While Marine grade plywood is technically “pressure-treated”, it is not soaked in or made with any special chemicals that increase its resistance to rot, mold, and moisture. The term “pressure-treated” is usually used to refer to plywood that has, in fact, been chemically soaked to improve its durability.
Marine grade plywood
Durability is the main upside of Marine grade plywood. It’s expected to last much longer outdoors than almost any other type of plywood. Because of it’s durability and resistance to moisture, Marine grade plywood is often used to build boats, homes, and more. The lack of knotholes and air pockets make it much more structurally sound.
The appearance of Marine grade plywood is also much better than that of regular plywood. It’s sanded on both sides and takes paint very well. It looks so good that you can even use it as top floor material.
It’s far less splintery and smoother than regular plywood. Marine grade plywood is also easier to cut and bend, making it much more suitable for a wide variety of construction projects. It’s also available in many different thicknesses and sizes.
Because Marine grade plywood is so high-quality, it may not be readily available in your area if you’re somewhat rural. It’s also more expensive than regular plywood.
This grade is both durable and strong while possessing dimensional stability as well. MDO is usually found in 4x8ft pieces. It can be had in a variety of thicknesses including ¾ inch, ½ inch, ⅜ inch, 1 inch, and ⅝ inch.
This grade of marine plywood is resistant to chemicals, weather damage, scratching and denting. For this reason, it’s often used for siding.
Marine grade plywood
Marine grade plywood is used in a variety of projects and locations. Its installation process varies based on how and where it’s being used, but it doesn’t require any specialized equipment and can be installed using the same method you would use to install most other types of wood.
Cut it to size with a jigsaw and cut along the grain lines to achieve a smoother cut. 3-inch exterior-grade wood screws should be used for bigger pieces and exterior projects. 1 screw every 12 inches or so should suffice, and caulk can be used to seal the seams between each piece if necessary.
