When you have a project that will be used on a boat or in another marine application, you likely will start looking for marine grade plywood. J. Gibson McIlvain (web link) recommends learning all you can about this type of plywood before you invest in it.
What Is Marine Grade Plywood?
Marine grade plywood is a product that is treated so that it can be used in marine applications. In order to be called marine grade, the product must meet the standards set forth by the APA’s Engineered Wood Association. However, those standards are not much higher than those for exterior grade plywood, which makes sense. While marine plywoods will be in contact with water more than the average exterior grade product, the other stresses they must endure are fairly similar.
So, what do these stipulations mean? In order to carry this certification, the plywood has to be free of any voids in its core, which could trap water and cause rot. Also, it will have few repairs to the core. Any glue must be weather and boil proof (WBP), so it can withstand the stresses of being used at sea. All of these stipulations are aimed at making the product as water resistant as possible.
What Is It Used For?
The most common application you would think of for marine grade plywood is boat building, and this is a common use. However, it is not the only one. There are numerous circumstances where the water resistance of marine grade wood would be ideal.
For instance, decking materials on the water, such as a fishing pier, should be marine grade, or at least have close to the water resistance of marine grade. Also, exterior woods used near the shore, such as in seaside homes, are exposed to a significant amount of water, even if they do not reach the waves directly. The water from the air and the sea spray can create problems in these areas, so marine grade products are quite important here as well. However, in these applications where the wood is not submerged, a few voids are allowable, and thus the buyer can save money while still benefiting from water resistance by choosing the plywood carefully based on the specific application it will be used for.
When shopping for marine grade plywood, make sure that the supplier is willing to ask about the application. This will help you save money while also giving you the right wood for the job. These questions help ensure that you do not greatly over pay for factors you do not need, while also ensuring that you do get the features to allow you to reach your goals for your finished product. The right supplier is the key to staying in budget and creating a successful marine based building project.