Are you considering purchasing marine-grade quality plywood for your next project, but you’re not sure whether you need it or not? Then this article series is for you. Whether or not a certain plywood product will bear the title “marine grade” or not depends largely on the manufacturer’s subjective designation. There are a variety of different considerations to keep in mind when it comes to choosing the right plywood for a certain application.
You may be surprised to learn that many products simply sold as exterior grade plywood don’t differ all that drastically from what the APA – Engineered Wood Association (formerly American Plywood Association) would consider “marine grade” quality. This grading can impact such details as plies, preservatives, glue, and veneers that may make a difference in the durability of your completed project. You’ll want to give special attention to the kind of conditions the plywood will be expected to withstand when you’re making up your mind about plywood product grading.
What Sets Marine Grade Plywood Apart?
Marine-grade plywood does have some advantages to offer you. First of all, the plies are fastened together using only Weather and Boil Proof (WBP) glue. In testing, this glue has been able to withstand over an hour of immersion in boiling water without the layers of plies coming apart.
Second, you’ll find that it has a void-free core. This lack of voids renders marine grade plywood more water-resistant than typical exterior grade plywood which may include voids. Because of this lack of voids, marine-grade plywood is unlikely to sustain damage to core plies from normal wear and tear.
Beyond these two main standards, marine-grade plywood can vary greatly in quality from supplier to supplier. If you want to determine that your marine grade plywood is of the highest quality, you can also look for British Standards 1088 or British Standards 6566. These British Standards refer to how premium the material is that is being used to make the plywood, with BS 1088 typically considered to be better than BS 6566.
If you’re following a set of instructions, you’ll want to look at them to determine which standard would work best for your particular design. The glue that’s applied as well as the different species used to construct the plywood’s core and face veneer will all play a big role in determining the durability of the plywood in varying surroundings and circumstances.
In the next article in this two-part series, we will look at two different applications that will serve to illustrate the need for either marine grade or typical exterior grade plywood. Both of these products are high in quality, with the marine-grade being slightly more durable than the exterior grade. But, as we will discover, there are all sorts of projects that would turn out just fine if you use exterior plywood instead of marine grade plywood. Knowing which projects require marine plywood and which ones don’t could help you to save some money on your next plywood construction project.