Pressure Treated Plywood vs Marine Plywood: What's The Difference?

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Plywood is a versatile material that is widely used in construction, furniture-making, and other projects. Two types of plywood that are commonly used are pressure-treated plywood and marine plywood. Both types of plywood have unique properties that make them suitable for different applications. In this article, we will compare pressure treated plywood vs marine plywood, highlighting their similarities and differences, so you can make an informed decision about which type of plywood to use for your next project.

Pressure treated plywood has been laced with chemicals that protects it from external elements that can cause damage. Marine plywood, on the other hand, is made with waterproof glue and is designed to withstand harsh conditions like being constantly exposed to water.

What Is Pressure Treated Plywood?

Pressure treated plywood is plywood that has been treated with chemicals to protect it from rot, decay, and insects. The most common chemical used for this purpose is chromated copper arsenate (CCA). The treatment process involves placing the plywood in a closed container, where it is surrounded by a pressurized mixture of the chemicals. The pressure forces the chemicals into the wood, ensuring that the entire piece of plywood is protected.

What Is Chromated Copper Arsenate?

Chromated copper arsenate (CCA) comprises of a mixture of chromium, copper and arsenic which are each toxic to living organisms in their own way. The chemicals are mixed together with water to make the pressure-treated wood product you buy at your local hardware store or lumber yard.

Benefits of Pressure-Treated Plywood

It can come in different grades depending on your needs.
You can paint or stain over it without any problems unlike other types of exterior wood products like cedar.

It is highly resistant to rot and decay. This makes it ideal for outdoor use, especially in humid or wet climates.
Pressure-treated plywood also has a longer lifespan than untreated plywood, making it a more cost-effective option in the long run.

Drawbacks of Pressure-Treated Plywood

Chromated copper arsenate used in pressure-treated plywood has been linked to causing certain types of cancers, reproductive problems, and other health issues when it enters your body through breathing or eating food that is contaminated with CCA-treated wood dust. When you use this type of wood in your projects, you should always wear a mask to protect yourself from breathing it in.

It can be more expensive than untreated plywood upfront.

Applications of Pressure Treated Plywood

Pressure treated plywood is often used in construction, particularly for outdoor projects such as decks, sheds, fences, and other structures that are exposed to the elements. It is also used in flooring, roofing, and other applications that require a durable and moisture-resistant material.

Cost and Availability of Pressure Treated Plywood

Pressure treated plywood is generally less expensive than marine plywood and is widely available at most home improvement stores and lumberyards.

What is Marine Plywood?

Marine plywood is a type of plywood that is specially designed to withstand the harsh conditions of marine environments. It is made from high-quality hardwood veneers that are bonded with waterproof glue. The result is a strong, durable, and moisture-resistant plywood that is suitable for use in boats, docks, and other marine structures.

Marine plywood is optimized for use in marine applications. It is made from thin layers of wood veneer, with each layer glued together with a waterproof adhesive. Marine plywood is available in a variety of thicknesses and grades, depending on the intended application.

The most common type of marine plywood is referred to as “exterior grade” or “marine grade.” This type of plywood is typically made from Douglas fir or Western larch and is designed for use in exterior applications where high moisture resistance is required. Marine-grade plywood must meet rigorous standards for both strength and water resistance and is typically used in boat construction or other outdoor applications where it will be exposed to the elements.

Types Of Marine Plywood

There are several types of marine plywood, but the most common is made from Okoume, Meranti, or Douglas Fir. Okoume marine plywood is made from a type of hardwood that is native to Gabon in Africa. It is lightweight, strong, and resistant to rot. Meranti marine plywood is made from a type of hardwood that is native to Southeast Asia. It is also lightweight, strong, and resistant to rot. Douglas Fir marine plywood is made from a type of softwood that is native to North America. It is strong and durable, but not as rot-resistant as Okoume or Meranti marine plywood.

Based applications, there are two types of marine plywood designed for use in interior applications:

Interior Grade

Interior-grade marine plywood is made from softer woods like spruce or pine and does not need to meet the same strength and water resistance standards as exterior-grade marine plywood.

Furniture Grade

Furniture-grade marine plywood is the highest quality marine plywood available and is made from hardwoods like maple or mahogany. It can be used for both interior and exterior applications but is most commonly used for furniture due to its high cost.

Benefits of Marine Plywood

Marine plywood is often made from better-quality wood.

It has a nicer appearance.
It last longer than pressure-treated plywood which makes it ideal for use in boat building.
It’s also safe to handle.

Its superior water resistance. This makes it an ideal choice for applications where the wood will be exposed to high humidity or direct contact with water, such as in boatbuilding, bathroom remodeling, or outdoor furniture construction.
Marine plywood also has a higher density than other types of plywood, which makes it more durable and resistant to impact damage.
It has fewer voids than other types of wood (voids are areas between the layers of wood veneer where there is no glue). This results in a stronger overall structure that can better withstand heavy loads without collapsing.

Drawbacks of Marine Plywood

You can’t use it on all types of projects.
It is too expensive.
It is not as versatile as pressure-treated plywood.

It is dense and waterproof, it can be difficult to work with using standard power tools.

Factors to Consider When Choosing Between Marine Grade Plywood vs Pressure Treated Plywood

When choosing between pressure-treated or marine plywood, there are a few key factors to keep in mind:

Durability and rot resistance

Both pressure treated plywood and marine plywood are treated to resist rot and decay, but marine plywood is generally considered to be more durable and rot resistant. This is because marine plywood is made with a higher number of plies and is constructed using waterproof glue.

Moisture resistance

Marine plywood is also more moisture resistant than pressure treated plywood. This is because marine plywood is constructed with waterproof glue and is designed to be used in marine environments, where it is constantly exposed to moisture. Pressure treated plywood, on the other hand, is treated with chemicals to resist rot and decay, but is not designed to be used in environments where it will be constantly exposed to moisture.

Chemical resistance

Both pressure treated plywood and marine plywood are resistant to chemicals, but marine plywood is generally considered to be more resistant. This is because marine plywood is constructed using waterproof glue, which makes it more resistant to chemicals than pressure treated plywood.

Cost and availability

Pressure treated plywood is generally more widely available and less expensive than marine plywood. This is because pressure treated plywood is produced in larger quantities and is used in a wider range of applications. Marine plywood, on the other hand, is a specialty product that is used primarily in marine environments and is therefore less widely available and more expensive.

Pros and Cons Of Pressure Treated Plywood vs Marine Plywood

Marine plywood vs pressure treated has its own unique set of pros and cons that should be considered before making a purchase.

Pressure Treated Plywood

Pros

More affordable than marine plywood
Available in a variety of thicknesses and sizes

Can be used for both indoor and outdoor projects

Cons

Not as durable as marine plywood

May warp or swell when exposed to moisture over time

Marine Plywood

Pros

More durable than pressure-treated plywood

Resists warping and swelling when exposed to moisture
Ideal for outdoor projects
Durable

Weather resistance (such as arsenic)

Cons

More expensive than pressure-treated plywood

Limited availability (thicknesses/sizes)
May contain harmful chemicals

Differences Between Pressure Treated Plywood vs Marine Plywood

There are several differences between marine grade plywood vs pressure treated including:

Weight

Pressure-treated plywood is much heavier than marine plywood. It is made with denser wood, which makes it more difficult to lift and carry. Marine plywood is much lighter than pressure-treated plywood, making it easier to work with and transport.

Appearance

Marine plywood has a nicer appearance and is often made from higher quality wood compared to pressure-treated plywood which tends to have knot holes, cracks, or other imperfections that reduce its overall appearance.

Voids and Gaps

Marine plywood is manufactured with a slightly thicker inner layer which prevents it from having as many voids or gaps compared to pressure-treated wood. This makes marine plywood stronger and more durable.

Cost

Marine plywood is typically more expensive than pressure-treated plywood since it’s of higher quality and uses better veneers and glue and also has fewer voids compared to CCA-treated wood.

Quality of Veneers

Marine plywood is manufactured with higher-quality veneers which means you’ll get fewer cracks or other flaws on your project making it durable and resistant to the elements.

Glue Quality

Marine plywood has a better quality of glue which means it will last longer and is less likely to warp, split or crack over time.

Ductility

Pressure-treated wood is known for being easy to bend with your hands while the bending strength of marine plywood is much more difficult to achieve without breaking or cracking the veneers.

Knots

Pressure-treated plywood has a lot more knots and weaker veneers which can affect its overall strength. Marine plywood, on the other hand, has fewer knots and higher-quality veneers making it a better choice for projects that require a lot of strength and durability.

Flexibility

Marine plywood is more flexible than pressure-treated wood which makes it a better choice for use in areas that are regularly exposed to high winds or other weather conditions.

Availability

Pressure-treated plywood is much more readily available at your local hardware store or big box retailer while marine plywood can be difficult to find.

Why is Marine Grade Plywood Better?

Marine-grade plywood is better than pressure-treated because it’s made with higher quality wood and has fewer gaps, voids, and other flaws which affect the overall appearance of your project.

It’s also safer to use because there are no chemicals involved and you don’t have to wear gloves or a mask which is important if your project requires handling the wood without protection.

Marine plywood is more expensive than pressure-treated but that’s because it uses better quality veneers.

Why Is Pressure Treated Plywood Better?

If you’re on a tight budget or can’t afford marine-grade plywood, pressure-treated plywood is a better choice because it’s much cheaper and can be used for many types of projects.

It’s also easy to cut and bend which makes it a good choice for do-it-yourselfers who don’t have much experience working with wood.

FAQs

What is the difference between marine plywood and treated plywood?

A: Marine plywood is a type of plywood that is constructed using waterproof glue and is designed to be used in marine environments, where it is constantly exposed to moisture. Treated plywood, on the other hand, is a type of plywood that is treated with chemicals to resist rot and decay.

Is marine plywood pressure treated?

Marine plywood is not pressure treated. It is constructed using waterproof glue, which makes it more resistant to moisture and chemicals than pressure treated plywood.

Can marine plywood be used for outdoor projects?

A: Yes, marine plywood can be used for outdoor projects, as it is designed to be used in marine environments and is therefore highly moisture resistant.

Is marine plywood more expensive than treated plywood?

Yes, marine plywood is generally more expensive than treated plywood because it is a specialty product that is used primarily in marine environments.

Can I paint marine plywood?

Yes, marine plywood can be painted, but it is important to use a waterproof paint and to properly seal any edges or cuts to maintain the plywood’s moisture resistance.

Is marine plywood better than gurjan plywood?

Both marine plywood and gurjan plywood are high-quality plywoods, but marine plywood is generally considered to be more durable and moisture resistant.

Conclusion

In conclusion, pressure treated plywood and marine plywood are both strong and durable options for a wide range of building projects. However, marine plywood is generally considered to be more durable and moisture resistant, making it the better option for projects that will be exposed to moisture and harsh weather conditions. While it is more expensive than pressure treated plywood, marine plywood is a specialized product that is designed to withstand the rigors of marine environments. When selecting the right type of plywood for your project, it is important to consider the specific application.