Does Plywood Rot?

Does Plywood Rot?

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Plywood is, of course, an extremely popular building material. That said, just like any building material out there, it has its issues.

One of the questions that many people have is whether or not it rots. Well, the simple answer here is that yes, plywood does rot.

Does Plywood Rot?

As mentioned above, the simple answer to this question is yes, plywood rots. Now, some types of plywood are more susceptible to moisture-induced rotting than others.

For instance, very low-grade plywood that has a lot of holes in it will absorb more moisture than other types.

This, however, is not the case if we’re talking about something like marine-grade plywood, which is made with a special adhesive specifically designed to prevent moisture absorption and rotting from occurring.

However, even these higher-end plywoods that are designed for marine use will eventually start to degrade.

What Causes Plywood to Rot?

Moisture is what causes plywood to rot, which is also what causes all other types of wood to rot. Plywood is not exactly the most moisture-resistant material around. If it is exposed to moisture for prolonged periods of time, it will start to absorb that moisture.

This could be in a basement that doesn’t have proper ventilation or it could just have been left outside in the rain for a few days. The bottom line is that plywood, no matter what type it is, is never going to be 100% totally waterproof.

Sure, some types of plywood may absorb water quicker than others, but eventually, all types will start absorbing water. Of course, if wood is constantly wet, it will start to degrade and rot. Your plywood will then start to crumble into pieces.

6 Ways to Prevent Your Plywood from Rotting

There are six different methods at your disposal that you can use to stop plywood from rotting, so let’s take a quick look at each of them right now. They are very similar to the ways plywood can be waterproofed.

1. Using an Epoxy Sealer

The most common and popular way to prevent plywood from rotting is by sealing it with an epoxy sealer. This substance not only makes the plywood waterproof but also much more durable. It really soaks into the surface of the wood and allows it to remain naturally colored. This is also one of the easiest methods of waterproofing your plywood.

2. Using Drying Oil

If you want to waterproof your plywood for marine and outdoor use, then drying oil is a great way to go. Drying oil allows the plywood to remain flexible and keep some of its natural moisture. If you are making a dock, a boat, or are working in a wet environment, drying oil is going to be one of the best methods at your disposal. This method actually strengthens the plywood and helps it deal with more moisture, as well as prevents deterioration due to water. Keep in mind, however, that this will not make the plywood 100% waterproof.

3. Using Oil-Based Paint

Another great way to help make plywood more waterproof is by sealing it using a layer of oil-based paint. Some people may recommend water-based paint, but oil-based paint is much more resistant to water. This paint will stop moisture from getting into the plywood, and allows you to color it to your liking.

4. Using Varnish

Another good way to help prevent plywood from rotting is by applying a layer of varnish to it. Varnish is a type of resin or mixture that you brush onto the plywood in a very thin layer. Varnish is also a bit glossy, which many people like. Varnished plywood will be able to resist moisture, mildew, and even salt water for many years to come. That said, it should never be totally submerged.

5. Liquid Latex

If you’re going for a really easy way to waterproof your plywood, using some spray-on liquid latex may be a good option. This is very easy to do, and very fast too. Moreover, it is also very effective at waterproofing plywood.

That being said, because it’s sprayed on, it can be hard to determine if you got enough on there for a proper seal. The other issue here is that it’s not very cost-effective and can be quite expensive. That said, if you do it right, it is an effective method, and even allows you to submerge that plywood.

6. Using PVA Glue

Another great way to make plywood more resistant to water is by applying a thin layer of PVA glue to it. PVA glue is clear, it dries thin, it bonds really well to plywood, and it ends up being completely waterproof too. That said, PVA glue definitely won’t last forever.

How to Fix Rotten Plywood

If you have plywood that is rotten, you simply need to sand out the rotted sections and then use an epoxy-based compound to fill the gap.

With that being said, this really comes down to the cost. If too much of the plywood is rotten, it’s going to be too expensive and take too much work. If this is the case, you may want to replace the plywood, not fix it.


As you can see, there are plenty of good ways to make plywood more resistant to water. Just consider your circumstances first, and choose the substance that suits that circumstance the best.