How To Waterproof Plywood – A Guide For Beginners

 “Wow, you are fixing the plywood again?” asked Robert to his father. “Yes, I forgot to keep it inside the garage, and again it became wet in the rain,” replied Mr. John. “I do have to catch a flight tomorrow, and your mom has the garage keys. Which means if it rains, plywood will become wet again”. Robert then said, “Don’t worry, I will make these plywood’s waterproof for you.”

Mr. John surprisingly never had to worry about leaky plywoods. Now, if you wonder what methods Robert followed, this is the best place to know about them. So, how to waterproof plywood? Don’t worry! These methods and step-by-step procedures to make waterproof plywood’s can be applied in any scenario, including the mentioned one.

If you’ve ever fixed or painted plywood that has leaked in the rain, you know how frustrating it can be to try and waterproof it. No matter which methods you try, water will seep through the wood eventually. That’s why Robert decided to help his father keep plywood waterproof – by following a few simple steps. In this blog post, you’ll learn about the different types of plywood, the best ways to waterproof them, and the sealant’s methods.

You’ll also find out about some of the non-recommended waterproofing methods, so you can decide for yourself what’s best for your situation. So finally, no more frustrating plywood leaks!

How To Waterproof Plywood

Can You Waterproof Plywood?

Can You Waterproof Plywood?

Plywood is a beautiful robust material that consists of thin layers of wood that are scraped from plies. These piles are glued together and utilized for a variety of constructional work purposes. Plywood’s are generally not waterproof, but they are relatively water-resistant. This material might resist very little moisture/ water but cannot stay in contact with water for a long time. This can cause the water to enter the layers of plywood one by one and ultimately destroy its structure.

As the water enters the layers of plywood, the individual layers expand, and the adhesive that keeps the layer connected cannot withstand the gradual expansion. After that, you might not be able to use these materials for your work anymore.

This is the time for you to know that you can save your plywood from water, even if they are not waterproof. To do that, there are plenty of methods, such as varnishing, using sealant, painting the woods, and more. We have discussed some of the measures as well as the step-by-step procedure to waterproof plywood.

Is Plywood Waterproof:

Is Plywood Waterproof:

Waterproofing plywood is key if you want your walls to stay dry in the event of a water leak. There are a variety of methods you can use to waterproof plywood, but the best way to choose depends on the plywood type and the sealant you use. Make sure the sealant is applying properly, so that the plywood remains waterproof for years to come.

In the event of a water leak, first assess the damage. If the damage is minor, you can try sealing the plywood with a sealant. If the damage is more severe, you may need to replace the plywood. If the plywood itself is not waterproof, you will need to install a raincoat system on the exterior of your home.

Waterproofing Plywood With Paint

Waterproofing Plywood With Paint

Plywood is a durable and affordable material that can use in a variety of applications. However, like any other material, it can damage by moisture and weathering. To protect it from these elements, you can waterproof plywood using paint.

The two most popular methods are using an oil-based formula or sealant, both of which work well. The best choice for you may depend on the type of wood your plywood is made out of and your climate conditions. One method is to use a sprayer and paint the plywood with an epoxy coating. Both methods are easy to use and result in a durable and waterproof plywood surface.

Waterproofing Plywood With Polyurethane

Waterproofing Plywood With Polyurethane

Waterproofing plywood is a great way to keep your home dry in the event of a water leak. Before applying the polyurethane, sand the surface of the plywood with 400-grit sandpaper. This will help the polyurethane adhere better and provide a smooth surface for the sealant to adhere to.

Once the polyurethane is applied and cured, you’re ready to finish your project. Be sure to sand the surface of the plywood again after applying the sealant and curing to ensure proper adhesion.. Waterproofing Plywood With a Sealant

In addition to using paint or polyurethane, you can also waterproof plywood with sealants. These products are available in aerosol and liquid forms, and both work well when applied properly. It is important to note that not all sealants are compatible with every type of wood, so be sure to read the instructions before beginning your project.

Again, sand the surface of the plywood before applying the sealant. Depending on the brand and formula of your chosen sealant, it may require two coats or more to fully seal the plywood. You can then finish your project by sanding again to assure a soft surface.

Waterproofing Plywood With Epoxy

Waterproofing Plywood With Epoxy

Waterproofing plywood can be a hassle, but it’s definitely worth it in the long run. Not only is it a practical solution, but it’s also a durable one. If you’re looking to waterproof plywood the right way, epoxy is the best option for you. This sealer takes a few hours to set, so make sure you schedule some time for it.

Epoxy is especially effective in high-traffic areas and near water sources. Once the sealer has been applied, it’s important to clean all of the surfaces surrounding the plywood before painting or finishing it off. Another great way to waterproof plywood is to use an epoxy sealer. This type of sealer is water resistant and resistant to moisture damage. So it is the perfect solution for plywood.

Which can use in wet places like bathrooms or kitchen. Regardless of which sealant you choose, always make sure to sand the surface before application. This will help avoid any ugly bubbling or peeling. And finally, be sure to read the instructions carefully before starting your project so that you apply the sealer in a correct and effective manner.

Waterproofing Plywood With Plastic Sheeting

Waterproofing Plywood With Plastic Sheeting

Waterproofing plywood with plastic sheeting is a quick and easy way to seal the surface and keep moisture out. Before starting the process, make sure the plywood is completely dry.

Then, apply the waterproofing material to the plywood using a sprayer or roller. Make sure the surface is completely cover and that the waterproofing material adheres to the plywood well. Let the waterproofing process take place, then remove the plastic sheet. The finished product should be dry and ready for use!

Necessities To Waterproof Plywood

Necessities To Waterproof Plywood

Other than the scenario mentioned above, you can face many difficulties if your plywood is not waterproof. Without waterproofing this material, you may have to replace it over hectic time. If you maintain the above steps, you can surely get-

  • Longer lifetime of plywood
  • Protection from dry rotting
  • Protection against the sun and humidity
  • Protection from splitting

Longer Lifetime Of Plywood


Without treating plywood properly, you will not be able to use it for a long time. It will not last more than two to three years. But by applying the above methods, you can get to use it for 40 years and above.

Protection From Dry Rotting


Waterproof plywood is required to protect the material from mildew as well as further deterioration. This is a widespread issue that affects nearly all exterior woods. Decomposing not only ruins the flawless outside appearance, but it also undoubtedly makes the wood fragile.

Protection Against The Sun And Humidity

Water can not only cause rotting but also destroy the entire structure from the plywood completely. This can also rip apart the plywood, which is why plywood sealant is necessary to protect it.

Due to the exposure to the sun, the wood begins to twist after a few hours in the hot heat each day. It may face discoloration. You need to make sure that the plywood is not exposed to the sun or water to preserve its look. But sometimes it is not possible to assure this as well. At that time, waterproofing methods might come in handy.

Protection From Splitting

Waterproofing plywood can reduce the chances of splitting as water doesn’t get to enter at all.

Few Methods/sealers For Waterproofing Plywoods And It’s Edging:

Few Methods/sealers For Waterproofing Plywoods And It's Edging:

Plywood is a modern-day “wonder” material that may be used for both indoor and outdoor applications. Plywood waterproofing is one of the most accessible techniques that may save you before the damage takes place.

Applying appropriate methods can ensure a long time saving of both money and work. Before using these methods, all other procedures needs to be done at first.

There are a variety of waterproofing techniques utilized to maintain plywood, and here are a few ways to consider:

  • Epoxy sealer
  • Penetrating oil
  • Spray or liquid latex
  • Varnish
  • Water-based sealant
  • PVA

1.Epoxy Sealer

Epoxy Sealer

One of the most common methods is to seal plywoods and their edges. Epoxy is commonly produced in the form of spray or paint.

Epoxy can be applied after sanding the plywoods and removing dirt, which dries fast and forms a more rigid layer. Some advantages of this method are:

  • It makes plywood stronger.
  • It can be reapplied without removing the previous layer.
  • Makes plywood waterproof and resistant to scratches.

2.Penetrating Oil

2) Penetrating Oil

Penetrating oil is another method that works for sealing plywood’s effectively. The oil may be spread evenly throughout the wood’s surface and absorbed to seal it.

After cleaning the plywood surface with wet clothes and sandpaper, a coat of hard oil is applied following the manufacturer’s guidelines.

You need to wait for 4-6 hours or 16 hours before taking it outdoors. A few advantages of this method are:

  • It makes the plywood moist and waterproof.
  • Maintains flexibility and durability of plywood.

Though it provides some safety, the continuous wind, sunshine, and rain might eventually dry up the oil closer to the surface.

So, try to ensure that the plywood on which it is applied will not be outdoors for a long time. Otherwise, this oiling has to be done frequently.

3.Spray Or Liquid Latex

3) Spray Or Liquid Latex

One of the cost-effective methods of sealing plywood is applying liquid or spray latex. After using a clean cloth and detergent to clean the surface, you have to let the plywood dry and then apply the liquid or spray the latex smoothly.

It does not take a long time; rather, it dries within 1-2 hours. For more protection, you can use another 1-2 coats more. Some benefits of this method are:

  • Latex binds with plywood and lasts a long time.
  • It is non-time-consuming.
  • Provides sufficient coverage.

Sometimes, liquid latex might be challenging to discern if you have enough plywood to seal it effectively.


4) Varnish

This is one of the best methods for sealing plywood’s without applying a thick coating layer. It can resist salinity, mold, and humidity for an extended period if it is not immersed. For that reason, it’s also ideal for outdoor use. Polyurethane varnishes are an excellent example of varnishing the edges of plywood where water enters the most.

To apply this special varnish, – masking tape, paintbrush, and a few items for protecting your hands will be needed. After applying the varnish on the edges, masking tape will come in handy to avoid the varnish getting into the surface. Next, apply another layer of varnish again for the best result.

  • This method gives a glossy finish.
  • It is perfect for maritime applications above sea level.
  • Keeps the moisture of plywood intact.

5.Water-Based Sealant

5) Water-Based Sealant

This method helps to cover the surface of plywood in a concise time. It is undetectable mainly and provides protection against water penetration. For applying this method, a sprayer and cloth rag will be needed too.

The coating is the first step that has to be done using a sprayer evenly. After it dries, the sealant has to be applied 1-2 times again for better water protection.

Make sure to apply the stain after cleaning the surface again. Then keep it for 24 hours before using it.

  • Plywood gets UV ray protection.
  • It keeps the moisture intact.

6.Polyvinyl Acetate Or PVA

6) Polyvinyl Acetate Or PVA

This is one sort of wood glue that is mainly used for binding books. It contains all features that can make plywood waterproof. Before applying it, make sure to dilute it with water which will help it to bind with the wood quickly.

How To Waterproof Plywood: Step- By- Step Guide

How To Waterproof Plywood: Step- By- Step Guide

Waterproofing plywood can be a simple and effective way to protect it from moisture damage. There are several methods you can use to waterproof plywood, depending on your specific needs and preferences. One common method is to apply a waterproof sealant or paint to the surface of the plywood.

This creates a barrier that prevents water from penetrating the wood. Another option is to use a waterproofing membrane or sheet, which is applied directly to the plywood and provides an extra layer of protection.

Whichever method you choose, it’s important to thoroughly clean and dry the plywood before applying any waterproofing materials, as this will ensure optimal adhesion and effectiveness. It’s also a good idea to periodically reapply the waterproofing treatment to maintain its effectiveness over time.

Step-1:Preparing The Plywood

It is crucial to make some arrangements before using any latex, epoxy, or paint. In this case, first, you have to clean the sheet surface of the plywood using a brush or a dry towel so that all dirt gets removed.

After that, to smooth down any uneven place on the surface, use a wood filler and wait for it to dry. This step will give a smooth finish while avoiding any waterproofing gaps.

Next, use a wet cloth to wipe down the sheet surface and after the wood filler dries. This method will make the sealer easier to bind with plywoods.

Finally, use sandpaper with 60- 80 medium grit and move it evenly back and forth. This will make the plywood even smoother. Then use a towel/ cloth to remove any plywood dust.

Step-2:Applying The Sealer

In this step. Apply any of the sealers that are mentioned above. If you choose to use a brushed on sealing technique, use a brush or roller as usual.

Make sure to use a medium-sized brush rather than the largest one, which will help apply the sealer evenly.

After covering the plywood with the first layer of sealer, keep an eye dry it before reapplying another coat. Certain substances and waterproofing requirements may necessitate the third coat as well.

If you choose to use a spraying method, make sure to follow the guidelines of the manufacturer. Otherwise, the coating will not evenly cover the surface, and spotty concentration will be seen too.

Step-3:Drying And Smoothing The Plywood

After choosing any of the mentioned methods, make sure to let the sealer dry properly. Sometimes it takes a few hours, or sometimes it takes a day to use it outdoors.

Finally, use a sandpaper grit again (120 or 80 grit sandpaper) and press it smoothly back and forth. This will eliminate any inconsistencies on the plywood surface.

Some Water-Resistant Plywood:

Even though there are various methods to waterproof plywood, you can still go for an alternative by buying a waterproof one for yourself.

Using the A-D system, you can choose the best waterproof plywood for yourself as A implies the highest appearance and D means the lowest.

So, while ABX has a better impression than CDX, the two have comparable resistance to water.

  • Boiling Waterproof Plywood:

“Boiling waterproof plywood,” or BWP, also known as “Marine plywood,” is a great choice to go for water-resistant plywood.

These sorts of plywood are not restricted to use in a specific place; rather, you can utilize them both indoors, outdoors, and also in humid areas.

It contains high-quality veneers and is treated with undiluted resins that are weather resistant. This product would be ideal for damp places such as a deck, kitchen, or restrooms too.

  • Boiling Water-Resistant Plywood:

Boiling water-resistant or BWR plywoods can work against the area where boiling water and steam are present most often.

  • ABX Plywood:

ABX plywood or marine grade plywood provides the best service both in associated marine areas and outdoor/ indoor places.

It has been carefully treated to withstand salt, dampness, and moisture, and it provides the finest and the most attractive surface.

  • ACX And ADX Plywood:

Both ACX and ADX plywood have similarities with ABX one and can be used for exterior renovations/ constructions.

  • Moisture Resistant Plywood:

The “Moisture resistant” or “MR” grade plywood is of great use indoors as it is not completely waterproof. It can withstand dampness and droplets but not excess moisture; hence it is ideal for humid areas.

Non-Recommended Waterproofing Methods:

Waterproofing plywood is important for a number of reasons – not the least of which is the fact that moisture can cause damage to the wood.

To ensure your plywood is waterproof, use one of the recommended waterproofing techniques. Keep in mind that each of these methods will cause the plywood to become weak and brittle over time.

Additionally, some methods – such as using silicone, hairspray, or paint – are not recommended Follow the instructions carefully to avoid any damage to your plywood.

How to Seal Plywood for Outdoor Use:

How to Seal Plywood for Outdoor Use:

Waterproofing plywood for outdoor use can be a challenge. But with the right instructions and precautions, the job can done successfully. First and foremost, be sure to seal the plywood the right way – with a second coat of sealant.

This will help save the wood from dampness and moisture damage. Next, sand the sides of the plywood and apply a sealant. Make sure to allow the plywood to dry for 24 hours before applying the waterproof tape. Finally, cover the surface of the plywood with waterproof tape. Happy sealing!

Final Words

If you have read so far, you surely have gotten an idea of how to waterproof your plywood. It might seem tricky at first, but once you start doing the work, everything will feel easy to you. Just be steady and don’t stop working till you get the result.

But before you stop reading further, let me remind you- keeping your plywood outside might cause damage to them, and it will cost both your money and time. Once the water gets into the layer, the adhesive will not be able to keep the layers intact.

As a result, you have to make the plywoods dry. Hence, try to keep them inside your home or garage but never in wet or humid areas. Or else, buy a waterproof one. Now since you have an overall idea of how to waterproof plywoods, you might go get it done and relax for a decade or more until it needs to be repaired again!

Frequently Asked Questions

1.Is Painted Plywood Waterproof?

Ans. Yes, painted plywoods can be made waterproof. Waterproofing options are obtainable in plenty. One of the most accessible methods of waterproofing is either the paint-on or spray-on method.

These are generally liquid latex chemicals that are applied to the plywood surface. This creates a protective layer that lasts for a long time.

2.How Can You Determine Waterproof Plywood?

Ans. Choose the plywood and cut it down to a size that will fit inside a cooker. Top up the pressure cooker with a sufficient amount of water to completely submerge the plywood. The oven should be preheated to 350°F and then make sure to bake for around 30–40 minutes.

If the plywood is delaminated, it will not be able to withstand the circumstances that we expect. But if the plywood retains its original shape, then it can be considered waterproof.

3.What Type Of Plywood Has The Most Long-Lasting Feature?

Ans. Marine plywood is the hardest and has the most long-lasting feature among all other available types of plywood. It is glued using high-quality superglue to ensure that the plies are extremely durable and resistant to moisture.

4.Does Marine Plywood Need To Be Sealed?

Ans. Yes, it is essential to seal marine plywood. Even though marine plywoods are specially made for wet and moisturized areas, it is vital to keep the moisture or water far from the pores of the woods.

This is why it is essential to apply a second layer of sealer to seal the plywoods. This will help the plywoods to last longer and work effectively.

5.Is It Possible To Find Waterproof Plywood?

Ans. Yes, it is possible to find waterproof plywoods. As I have already mentioned above, waterproof plywood is a moisture-resistant material that is used for a variety of functions. It’s ideal for outdoor use since it can withstand a variety of weather conditions too. Some of the waterproof plywoods are- “BWR,” “ACX,” or “ABR” plywoods.

6.Can You Use Paint To Waterproof Your Plywoods?

Ans. Waterproofing compound adheres well to plywood. Even after a matte or smooth work on plywood, it will still be permeable enough to bind with paints or liquid sealers. This means you can use paint to waterproof your plywoods.

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