5 Easiest Ways To Waterproof Plywood For Exterior Use

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Jacky C

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Have you ever actually wondered what would happen to your plywood structure whenever a storm or heavy rain hits your house? Well, you will certainly have to go through the problems you would not ever want to face. But that is where the waterproofing of plywood comes in to save the day and make your whole experience better. It does not precisely matter if there is a hailstorm or it has been raining for a whole day; your plywood won’t budge if it is properly waterproofed, that is. But do you know how to seal plywood?

Waterproofing of plywood requires different substances, environments, methods, and techniques in order for the waterproofing to work correctly. We can use hard wax oil, varnishes, specific sealers, latex, and some other materials to make the plywood waterproof. It also depends on the woodworkers’ preferences on which method they would choose to waterproof their plywood.

Now you might be thinking about how these methods actually work and how can you implement them, right? Well, after reading all the methods mentioned below briefly, you will definitely be able to get the answer to how to waterproof plywood.

Top 5 Methods To Waterproof Plywood And Make It Durable!

Do you know why I have talked about durability along with the actual problem, which is waterproofing? Well, the methods we are going to discuss can ultimately solve both of these problems, so why not make your plywood durable too?

1. Using The Hard Wax Oil

If you have no idea how to seal plywood, then you can definitely go with this method. The reason why this method can be suitable for most beginners or inexperienced woodworkers is that it does not require much work to implement the method.

Other than that, if we talk about how hard wax oil can be a great choice here, then note that wax oil can offer you all-in-one services for your plywood. It can make your plywood waterproof, sturdy, durable, and shiny at the same time. Not only that, but it can actually also save your plywood from environmental change as we are talking about the outside usage here. You will not have to use any other product other than wax oil to see impressive results.

How to waterproof plywood with hard wax oil?

You can simply follow all the steps mentioned below to get your work done:

  • Thoroughly clean the plywood with a cloth or any other soft material. It is better not to use any kind of liquid substance to clean the surface, but if there are stains that are not removed, you can use detergent or soap.
  • After cleaning the plywood, evenly spread the wax oil on the surface of the plywood.
  • Let the plywood sit overnight or at least 6 hours to get the best results.

2. Implying Polyurethane Varnish

Varnish is quite a common product or substance for every woodworker as it is used in many places when it comes to woodworking. Well, in this case, varnish can again solve your problem of waterproofing. If you are finding the solution of how to waterproof plywood, varnish can be your best plywood sealer. And yes, make sure that you are getting polyurethane varnish as it is the one that will work the best here.

It will help your plywood to remain waterproof and durable for the longer term. You will also not really have to worry about the excessive heat or chilled environment because of the enhanced properties. The last thing you would want to note here is that varnish will be applied on the edges or the corners, not on the surface, like the method we discussed previously.

How to seal plywood with polyurethane varnish?

Following are the steps that you will have to follow for the sealing process:

  • You will again first have to clean the plywood properly so that nothing would remain on the surface, not even a single particle of dust.
  • After that, you will have to get a brush so that you can dip it into the varnish and start applying it to the wood.
  • If you don’t have a brush, then I would suggest you get one before starting the process. No other tools will work here other than the brushes, as they will tend to apply the varnish evenly on the edges and won’t go off in any other direction.
  • It is also a great idea to cover the surface of the wood with tape or plastic so that the varnish would not touch it.

3. Waterproof plywood sealer

If you have ever actually been to a hardware shop, you would definitely know that there are probably tens of waterproof plywood sealers available that can help you out. But the thing is, can you really get any of them, and will they be able to do the work? Well, you will first have to check the properties and see if they can work well on plywood or not and if those plywood sealers can offer durability and perfect sealing or not.

If you have made sure of all of these things, you can simply get your hands on any plywood sealer. And yes, do not forget to opt for a sealer that can be applied on the surface, too, for the most feasible experience.

How to waterproof plywood with a sealer?

Check out the steps below and make sure to follow them thoroughly:

  • The significant thing that you should keep in mind when applying anything to wood is that you should clean the wood properly. The same case goes for this scenario, as you will have to clean the plywood properly with a cleaner or a simple cloth. Just make sure that there are no stains or dust particles left in the end.
  • Now you can proceed with the application of plywood sealer. It is actually a good idea to use a paintbrush to easily wipe the sealer throughout the surface.
  • After applying the sealer, leave the wood be for more than eight hours if it is water-based; otherwise, leave it for a day in case of oil-based sealer.

4. Use of Latex

If you are really willing to go the extra mile to make your plywood completely waterproof, then this method will also suit you the best. Not only that, even the beginners who don’t know how to waterproof plywood in any way can implement this method. This time, you will again have to visit a hardware store and ask for latex. Latex is usually not that expensive, so you can expect to pay less than the other methods, and it will also offer feasibility while applying.

Other than that, latex also tends to offer complete protection. If you are using it on the plywood that has been placed outside, you will not have to worry about rainy weather or excessive heat, as latex will protect it at all costs. Just make sure to get the latex that is compatible with wood and not any other material.

How to seal plywood with latex?

To seal the plywood with latex, you will have to implement the steps mentioned below:

  • You might now be tired of reading it, but you will again have to clean the wood properly with several cloth pieces or any type of mixture that would remove dust and stains. It is undoubtedly and really one of the most critical steps when it comes to waterproofing the plywood, so it is better not to ignore it.
  • After the cleaning process, you can use a brush to apply the latex on the whole wood surface along with the edges and the corners. Do not forget to implement the latex evenly at all places for better protection.
  • One of the best and greatest things about latex is that you don’t have to leave it overnight or for several hours. An hour or two is quite enough for it to dry correctly, and you can use it after that period.

5. Use of stains (Water-Based)

If you are actually the type of person who likes their plywood shiny and bright, then you might not really want to get your hands on a water-based stain. It is undoubtedly true that water-based stains can make your plywood waterproof and durable, but at the same time, they are really dull in color and do not offer a bright look to the wood. So if you are comfortable with it, it is another excellent option for your plywood.

Another suitable property of stains is that they can really save your plywood from UV lights. This means that you will not have to worry about heat making your plywood look worse than ever after some time.

How to waterproof plywood with stains?

For the waterproofing of plywood with stains, you will have to proceed through the following steps:

  • Yes, again, you will have to clean the plywood with any kind of cloth that can easily remove the dust.
  • After that, you will need a spray for spraying purposes. The reason why we are not using brushes here is that stains are really light and won’t properly stick to the brush. That is why it is better to spray it rather than going for the brush.
  • Then you can leave the wood for a day or two to let it dry completely.

Frequently Asked Questions!

Can I paint plywood to make it waterproof?

Paints can surely make plywood waterproof. But whenever you are buying paint for your plywood to make it waterproof, make sure that it is latex based otherwise, it won’t be able to offer protection to your wood.

What is the best way to seal plywood?

Using latex is definitely the best way to seal plywood. It is easy, efficient, and consumes less time as compared to other methods. Not only that, latex tends to offer complete protection from all types of weather changes.

I would suggest you FamoWood 40042126 from Amazon as it dries quickly and does not allow the wood to crack in any case. Not only that, it is suitable for outside use too and can be painted with ease!

How do you paint and waterproof plywood at the same time?

You would require latex-based paint if you want to do both of the things at the same time.

How long will plywood last outside?

If you have adequately implemented the methods, you can expect your plywood to offer you more than 40 years without creating any type of hassles.

Should you go for exterior plywood?

If you don’t want to hassle yourself with all the waterproofing and protecting methods, you can go for exterior plywood, but it is undoubtedly costly.

Should I seal plywood before painting?

Definitely! If you really want your plywood to survive longer, you should seal it before thinking of painting.

Does rain ruin plywood?

If you have used a substance or any method mentioned above, you will not have to worry about rain ruining your plywood. If you have not done anything and have simply placed the plywood outside, you might have to face the consequences later.

Does plywood absorb moisture?

Like all the other types of woods, plywood also absorbs moisture. That is why we use different methods to protect it at any cost.

Is plywood cheaper than solid wood?

Absolutely! Plywood is significantly cheaper than solid wood, and it still offers some good properties.

Is plywood sturdy and robust?

Plywood is considerably sturdy and robust, and that is why most people prefer it for outside use.

The Verdict!

So do you now know how to waterproof plywood or not? Well, you would surely do! Still, you can go through the methods again and see what the things that are required can solve your problems. And, of course, do not forget to use the right tools while applying or spraying the products if you don’t want your experience to turn into something drastic.

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