Marine grade plywood generally refers to plywood constructed from one of two species: Douglas Fir or Okoume. Both types of marine grade plywood are used in exterior applications in which the final project must be capable of withstanding very high moisture contents or even complete submersion – projects such as boat building, piers, docks, and decks. Marine grade plywood is, in basic terms, waterproof plywood.
Marine grade plywood must be water resistant, strong, lightweight, and easily bendable. In terms of functionality, Douglas Fir marine grade plywood is top notch; it’s extremely strong, is of medium weight, and bends well.
Douglas Fir is a naturally strong and weather resistant species, so Douglas Fir marine grade plywood is exceptional in all aspects – except appearance. This type of marine grade plywood meets the high standards for weather and water resistance, but it is permitted to have a number of aesthetic imperfections. Knots and patches are allowable, as long as they do not interfere with the functionality of the Douglas Fir marine grade plywood, and the surface of this plywood is sometimes a bit uneven.
However, this type of marine grade plywood is quite inexpensive, so Douglas Fir is therefore often the species of marine grade plywood chosen to be used in areas of the project that will not be seen.
The second most common type of marine grade plywood is the species Okoume. Unlike Douglas Fir marine grade plywood, Okoume marine grade plywood is the species of choice for use in the areas of projects where appearance is important.
Okoume marine grade plywood finishes wonderfully, and the finished boards are often described as having a glassy sheen. The wood has a consistent appearance, and its grain is tight and attractive. What’s more, Okoume marine grade plywood is very durable and lightweight, two important characteristics for a marine grade plywood.
Although the Okoume species itself is not particularly waterproof, when treated with a WBP phenolic glue and laminated with a Fir core, Okoume marine grade plywood is nearly impenetrable. Okoume marine grade plywood is a beautiful plywood and is perfect for use in applications where it is to be painted, fiberglassed, or epoxied.
Both Okoume and Douglas Fir marine grade plywood species have their place in outdoor projects. Both are essential components in many marine projects, and both are available in varying qualities. A high quality lumber dealer like McIlvain Company will be able to provide you with a wide selection of fine marine grade plywood to help you complete your project.