Marine plywood is manufactured in a manner similar to traditional plywood and features water-resistant hardwood construction and strong waterproof adhesives not commonly found in regular plywood that make it safe for use on boats or in constructions that see regular exposure to the elements. Common applications for marine plywood include the construction of seagoing vessels, patios, decks and gazebos.
The hardwoods selected for marine plywood are often Douglas fir or Western larch, unlike the materials used in traditional hardwood, which may include a fascia of many different hard and soft wood types. Marine plywood requires at least grade B wood, which may contain knots but has no holes that could decrease the water resistance of the pieces. Like standard plywood, higher-quality marine plywood often features more sheets per inch, making it stronger and more durable. A waterproof adhesive holds the plywood together, ensuring that exposure to moisture cannot break down the glue over time.
Marine plywood may lack the rot- and decay-resistance of some standard pressure-treated plywoods that use cedar and other woods that have this resistance naturally. Because the wood used in the construction is only water-resistant, marine plywood still requires proper sealing to prevent eventual breakdown of the materials. This includes caulking in seafaring applications and finishing for outdoor structures.