Clearing Up Confusion Related to Marine Grade Plywood

Many people don’t know when to use marine-grade plywood, even when they think they do. Of course, if you fail to use marine-grade products when they’re truly warranted, the durability and longevity of your application will be compromised. On the other hand, though, if you use marine-grade plywood when it isn’t really needed, you’ll be busting your project budget for no good reason.

Here at McIlvain Company, we always respond to those inquiring about our marine-grade plywood by asking questions about the intended end use of the material. Consider the following before deciding whether or not to purchase marine-grade plywood for your next project:

Why Confusion Exists

The industry itself is partly to blame for the confusion that exists regarding marine-grade plywood. The term “marine-grade plywood” is used loosely by many builders, and even plywood manufacturers use the term more liberally than they should.

Adding to this confusion, the APA (Engineered Wood Association) standards for marine-grade plywood aren’t much higher than those for exterior-grade plywood, meaning consumers often make the mistake of believing that the two are interchangeable.

What To Look For

If you do need true marine-grade plywood for a project, you need a product with the right combination of plies, preservatives, veneers, glues, and manufacturing techniques. By definition, all marine-grade ply is free of voids in the core, as such voids can trap water and cause internal rotting. Also, the glue in the plywood must be Weather and Boil Proof (WBP).

There, however, the official standards governing marine-grade plywood stop. As a result, there are several variations of marine-grade plywood, so if you want ply that will stand up to serious water, you’ll want to look for BS 1088 and BS 6566 grades.

Applications That Warrant Marine-Grade Ply

Clearly, the boatbuilding industry relies on marine-grade plywood; however, just having plywood labeled “marine” will not ensure that the material is right for the job.

In boatbuilding, the perfect combination of water resistance, face appearance, and bending ability is required, and the plywood’s weight should also be considered. Water resistance requirements mean that BS 1088 or better should be used when the wood will be fully immersed in water.

Applications That Don’t Warrant Marine-Grade Ply

Some builders or buyers think that just because an application will be subjected to weather, marine-grade plywood is necessary, but they’re wrong. For external structures of seaside homes or other structures on ocean-front property, marine-grade ply is actually not necessary unless those structures are expected to be fully submerged.

You certainly could purchase premium marine-grade ply for these kinds of structures, but because a high quality exterior-grade plywood would suffice, purchasing marine-grade ply would truly be a waste of money.

Supplier Information

If you contact a lumber supplier and ask about marine-grade plywood, you should expect to be asked about the end use you have in mind. If you are not asked, then beware! The lumber supplier could be trying to sell you a more expensive product that you don’t really need.

At McIlvain Company, though, we listen to your precise project intentions and try to guide you in the right direction. We’ll help you find the materials you need for your project, without trying to lead you towards more expensive materials that aren’t necessary to get the job done.

For over 200 years, McIlvain Company has been a leader in the lumber industry. With a huge inventory of exotic and domestic hardwood and softwood lumbers, in-house millwork capabilities, and a staff with unmatched expertise, it’s no wonder that McIlvain is one of the country’s most reputable lumber dealers. For more information and to see McIlvain’s full inventory, click here to visit them online. And for insider tips and woodworking tricks, check out these selections from the McIlvain Lumber Blog: