Can Plywood Be Used Outside?

Can Plywood Be Used Outside?

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Plywood is one of the most common and popular building materials out there. Yes, it is very commonly used indoors, but what about outdoors? Can plywood be used outside?

The answer here is that yes, plywood can be used outside, but it does really depend on the type of plywood in question. Not all types of plywood are suitable for outdoor use, whereas a few certainly are. Let’s talk specifics about using plywood outdoors.

Can Plywood Be Used Outside?

Yes, plywood can be used outdoors, as long as you are using the right type of plywood, as not all types of plywood are best for outdoor use. This really comes down to interior plywood vs exterior plywood. The differences between interior and exterior plywood can be quite large.

Interior plywood generally focuses on appearance, having a very smooth finish that is free of visible defects. It’s meant to look good, as it is often used for furniture and cabinetry.

Alternatively, exterior plywood generally doesn’t look all that nice and often has many holes and knots in it. However, exterior plywood doesn’t need to look good, it just needs to be strong and weather resistant. It’s often made out of dense hardwood and is designed with durability in mind.

One of the defining features is that exterior plywood is glued together using high-quality waterproof adhesive. This helps to stop it from delaminating at the edges, splitting, and crumbling into pieces when exposed to fairly high levels of moisture on a regular basis.

That said, even this type of plywood is generally not 100% waterproof, aside from a few specific types.

Will Plywood Rot Outside?

If you happen to use interior plywood for exterior purposes, then yes, you can expect it to absorb water, degrade, and rot, and rather quickly too. If you use interior plywood outdoors, and it is exposed to moisture on a regular basis, you can expect it to last just a few years before it rots, at the most.

However, if you use high-quality exterior plywood, it really shouldn’t rot. This is especially the case if you have painted it or treated it with some sort of waterproof layer. If you build something outside using high-quality exterior plywood, rotting should not be an issue at all, at least not for many decades to come.

How Long Does Plywood Last Outside?

If we are talking about high-quality exterior plywood, such as the ones we will discuss below, you can expect it to last for around 35 to 50 years at the most. It will, however, depend on the exact type of plywood in question, as well as how it has been treated.

4 Best Types of Plywood for Outdoor Use

There are four main types of exterior-grade plywood that are suitable for outdoor use, so let’s take a look.

1. CDX Plywood

One of the best and most common types of plywood designed for outdoor use is CDX plywood. The first two letters mean that this type of plywood is ideal for construction purposes, such as weight-bearing applications.

The X simply means that CDX plywood is designed for exterior use. This is an affordable type of exterior-grade plywood, yet can still stand up to rain and high levels of moisture. There are even higher grades of exterior plywood, including ABX, BCX, and ACX.

2. T1-11 Plywood

T1-11 plywood is a very special type of exterior-grade plywood that is designed to be used as siding for houses and sheds. It has a very rough appearance, nothing pretty to look at, and it might even have grooves designed to mimic the appearance of vertical ridges.

This type of plywood is easy to stain or paint, so you can match it to the color scheme and appearance of the rest of your home. This is in fact one of the most durable types of exterior plywood out there.

3. Pressure-Treated Plywood

If you are looking for one of the most waterproof types of plywood out there, you might try using pressure-treated plywood. Using a special process that involves high levels of pressure, this plywood is infused with various chemicals, such as chromate copper arsenate, copper azole, borates, and more. These chemicals allow pressure-treated plywood to be extremely resistant to moisture, mold, and mildew.

4. Marine-Grade Plywood

Perhaps the best type of plywood to use for exterior purposes is marine-grade plywood. First, the adhesive used to hold everything together is 100% waterproof, even to the point where it can be submerged or partially submerged in water for prolonged periods.

Also, the core is made with very high-quality sheets that are free of knots and holes. This eliminates the occurrence of water pockets inside the plywood. Boats, docks, and other seaside structures are often made with this material.

5 Common Outdoor Plywood Uses

Let’s take a quick look at some of the most common uses for outdoor plywood that you might come across.

1. Building Sheds

Basic CDX plywood is a great option to consider when it comes to building simple structures like outdoor sheds for garden and storage purposes, especially when they need to last for a long time in relatively poor weather conditions. Exterior plywood is always best for this purpose.

2. Making Storage Boxes

Just like plywood is great for larger sheds, it also makes for a good option to use when making smaller outdoor storage boxes, such as for gardening tools and other storage purposes.

3. Siding for Houses

Another very common use for exterior-grade plywood is for the sheathing and sidings of houses. It’s a great way to cover the exterior and protect the rest of the house’s frame from damage, and if you choose the right kind, it’s also easy to stain and paint, so it matches the exterior of your home.

4. Decks and Patios

Yet another common use for exterior grade plywood, any kind of it realistically, is for making the floors of decks and patios. If you need a cost-effective wooden building material that can handle lots of foot traffic and is weather resistant, plywood is the way to go.

5. Docks, Boats, and More

In terms of marine-grade plywood, as the name implies, this is perfect to use for marine or seaside applications. This can include building boat hulls, seaside sheds, docks, piers, and anything else of the sort.

4 Alternatives to Plywood for Outdoor Use

Let’s take a quick look at some alternatives to plywood for outdoor use.

1. OSB

OSB is almost as durable as plywood, and is also water resistant, although not quite as much as high-grade exterior plywood. However, it is very affordable, easy to work with, and eco-friendly too.

2. HDF

HDF or hardboard is another good outdoor material. It’s not as good as plywood, but still fairly weather resistant. It’s fine to use as long as you don’t live in an area with excess levels of moisture.

3. PU Board

Polyurethane board is essentially made out of plastic and is therefore great for applications that require a lot of weatherproofing. It’s also durable, but do keep in mind that it doesn’t look all that nice.

4. Solid Wood

Sometimes there’s just no better option than real wood, especially in terms of structural integrity and appearance.

Summary

You should now have all of the info you need to make informed decisions about the best outdoor building materials, particularly plywood.