What Is Marine Grade Plywood?

What Is Marine Grade Plywood

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When it comes to popular building materials, plywood is one of the top ones out there at this time. It is an extremely versatile building material that has literally dozens of uses. That said, there are many different types of plywood out there, and which one you choose is going to depend on the application at hand.

Today, we are here to look at one specific type, marine plywood. Let’s figure out what it is, how it’s made, what it’s used for, and more.

What Is Marine Grade Plywood?

First off, what you need to know is what the basic version of plywood is all about. Plywood is made by taking wood veneers, which are long and thin strips of wood, and making layers out of them, with subsequent layers seeing the layers of veneer be perpendicular to one another. This ends up creating a so-called cross-grain pattern, which is known for being very strong, particularly when compared to other types of engineered wood.

Yes, plywood is a type of engineered wood, with engineered wood being any wood product that is made out of real wood, which is broken down, and then reassembled into something that looks like solid wood, generally using a mixture of adhesives, chemicals, heat, and pressure.

The important thing to note here is that marine grade plywood is a very special type of plywood designed for applications that involve a lot of moisture. It is made for applications where that plywood will need to be able to withstand very high and constant levels of moisture, such as when being out at sea.

In case you are confused about the difference between normal plywood and marine plywood, no worries, because we will cover this below.

How Is Marine Grade Plywood Made?

In its most basic form, marine grade plywood is made in the same way as normal plywood. Strips of wooden veneers are laid beside each other to create a layer, a second layer is then created by laying the veneers perpendicular to the first layer, and so on and so forth, until there are a plethora of layers that end up creating a solid board that features a cross-grain or cross-lamination pattern.

Now, the difference between the making of regular plywood and marine grade plywood is that marine grade plywood is generally made with high-quality hardwood such as Douglas Fir or pine. In other words, this type of plywood is made 100% out of hardwood, whereas regular plywood is usually made out of softwood. Moreover, normal plywood is usually made with just a few layers of thick veneers, usually no more than 11 layers, whereas marine grade plywood is made with much thinner veneer strips, but with more layers, sometimes up to 21 or more.

The other difference here is that normal plywood is sometimes treated to make it more water resistant, whereas marine grade plywood needs no such treatment.

What Grades of Marine Plywood Are Available?

The next thing that you need to know here is that not all marine grade plywood is the same. In fact, there are a few different grades of marine grade plywood, and which one you choose is going to depend on the task at hand, as well as what your needs are. There is a whole lot to cover in terms of marine plywood grades, enough to write a massive article on the topic alone, so we aren’t going to go into much detail here.

That said, there are a few primary types or grades of marine plywood that you may have access to, and these include BS 1088, BS 6566, AS 2272, A-A, A-B, B-B, MDO, and HDO.

What Are the Advantages of Marine-Grade Plywood Over Regular Plywood?

The simple reality here is that marine grade plywood does have a few advantages when compared to regular plywood, so let’s take a look.

1. More Structural Integrity

One of the advantages that comes with marine grade plywood is that it is more structurally sound than regular plywood. Because regular plywood is made with just a few layers of thick softwood veneers, there are often gaps and voids within the boards that cannot be seen from the outside, which of course does not do you any favors in terms of structural integrity and durability. Due to the construction of marine grade plywood, it does not contain these voids or gaps, and is therefore much more structurally sound.

2. It Can Handle Constant Moisture

Marine grade plywood is the only type of plywood out there that can be constantly submerged in water without fear of degrading, warping, cracking, or crumbling into pieces, which after all is why it is called marine plywood. It does not have its name for nothing.

3. It Does Not Require Additional Chemical Treatment

Some regular plywood is treated with chemicals for additional moisture resistance, but marine grade plywood requires no such treatment, thus making it more eco-friendly.

4. It Holds Screws Better

Because marine grade plywood is made with many thin and dense layers of hardwood veneer, it is much better able to hold onto screws and other fasteners than normal plywood (which is already good at holding screws as is).

5. Easier to Cut and Sand

Also due to the hardwood construction of this type of plywood, it is much easier to saw and sand without causing a bunch of tear-out and splintering.

What Is Marine Grade Plywood Used for?

The main uses of marine grade plywood include in the building of ships, for docks and wharfs, for floating docks, or any other application where the wood will constantly be exposed to high humidity levels and direct moisture, such as a structure that stands close to the sea and is often hit by waves and sprays of saltwater.

When wood and water come together, it’s usually marine grade plywood that you need.


There you have it folks, everything you need to know about marine-grade plywood! It’s quite the high-quality type of plywood, and when water is involved, it’s the best way to go.

Just make sure you don’t confuse it with exterior plywood.