how to make wood waterproof

How to Waterproof Wood for Bathroom: 4 Different Techniques

When wood is not treated, there’s a significant chance it will rot or warp over time – especially when it comes in contact with water.

That’s why you need to learn how to waterproof wood for bathroom. Those small pieces of furniture or objects in your bathroom that are made of wood may need extra help from a finish to not corrode. And here, we’ll teach you how to make that possible.

Waterproofing wood is not easy, though. So, you’ll have to take every single step and factor stated in this article into account.

We’ll teach you four different ways to do it, as well as how to prepare everything so you can get to work as soon as possible.

Keep reading and learn what you’ll need to do!

How to Prepare the Wood and Yourself?

First and foremost – make sure you have everything you need to get the waterproofing effect going. And sure enough, you’ll have to start by preparing the piece of wood you want to cover and gathering all the safety items and tools necessary.

Prepare the Surface

Prepare the Surface

Wood pieces often have uneven or imperfect surfaces. This causes waterproof finishes not to stick correctly. Eventually, the finish may fall or just don’t do its work. So, you’ll have to prepare the wood by getting rid of these imperfections.

At the same time, you want the whole surface to be utterly clean, so you can apply the waterproof mixtures at once.

For both of these purposes, you’ll need the following:

  • 220-grit and 150-grit sandpaper
  • Broom or brush
  • Dustbin
  • Vacuum (optional)
  • Lint-free cloth

Once you have these items, then proceed with the following steps:

  • Start sanding the whole surface you want to cover. Use either 150 or 220 grit sandpaper. If the wood surface is too rough, then use 150-grit. But if the surface is almost smooth, then 220-grit sandpaper will suffice.
  • Sand the surface following the grain. Do not forget about crevices and complicated or irregular areas. Try to cover everything, so the whole surface is prepared for the waterproofing process.
  • Remove any remains from previous finishes. Also, get rid of imperfections.
  • Proceed to clean with a broom or brush. And then deposit everything on a dustbin. You can use a vacuum instead to make the process fast.
  • Finish by dipping the lint-free cloth on the water for a few seconds and then clean the surface off debris and dust. Follow the grain for better results.

You should be left with an entirely smooth and ready-to-be-waterproof surface.

If there are still imperfections and/or areas that feel too rough, then you can repeat the process. Don’t forget to leave everything as clean as possible.

Prepare Yourself

After gathering all the items and preparing the wood surface, then you should prepare yourself. This is mostly about gearing up safety equipment and wearing the right clothes.

Here’s what you’ll need:

  • Rubber or silicone gloves
  • Safety mask
  • Sturdy boots or shoes
  • Long sleeve shirt
  • Pants

Wearing all these pieces will be enough to get ready for waterproofing wood. So, don’t hesitate, and let’s get going!

How to Waterproof Wood for Bathroom in 4 Different Methods?

While learning how to make wood waterproof, you should consider several factors.

First, you need to know which surface you want to coat. You’ll have to prepare it following the previous section.

Second, you want to have a proper area to work. We recommend an outdoor space like a porch, patio, or yard. If you’re looking to waterproof an unmovable wooden object or floor, then make sure every window around is open. Then use a fan to circulate air.

Lastly, clean everything nicely before starting. Even if you don’t have to prepare the surface beforehand, we recommend getting everything as clean and tidy as possible before starting. This will prevent any mess.

Without much further ado – here are 4 methods you can use to waterproof wooden surface in your bathroom:

Method 1: Waterproofing Wood with Oil

Waterproofing Wood with Oil

This is an excellent way to waterproof wood, mainly because it delivers a stunning result. Apart from that, it offers superb durability and requires little to no money at first. So, you can get any surface waterproofed with oil without wasting your money.

Here’s how:

Pick the Right Oil

The first thing you’ll have to do is pick the ideal oil. There are various kinds to consider: tung, linseed, walnut, teak, and hard wax oil.

We recommend teak oil for an exquisite finish, as it looks superb. For durability, hard-wax oil would be the ideal choice. If you want a wet-like appearance, then you won’t hesitate and get tung oil. And lastly, linseed oil can be excellent for objects.

As for drawbacks, walnut oil can be an allergen for allergic people – so don’t apply it in surfaces that come in contact with people’s skin. Hard-wax oil is durable but tends to leave a super-thick surface. Then, you’ll find tung oil to be amazingly expensive. And linseed oil can be a little toxic when applying.

Each one offers a different result, so you’ll have to pick accordingly.

Create the Mixture

Once you’ve figured out the ideal oil for your waterproofing, we recommend strengthening the oil using a sealant.

Here’s how:

  • Go to the supply store and look for turpentine and apple cider vinegar. They help to strengthen the oil and leave a better-looking surface.
  • Pour oil in a bowl and fill it in half. Then fill a fourth of the bowl with the sealant (turpentine). Then add the rest with the apple cider vinegar.
  • Mix until the solution is totally blended and looks shiny. This solution should make the oil look thinner than before.

With the concoction ready, you can get going.

Apply the First Coat

Start by applying the first coat of the mixture. This will set the base so you can reapply later and make the waterproof cover extra reliable.

Here’s how:

  • Pour some of the mixtures in a rag. Then start to gently rub the rag with oil on the surface of the wood. This should leave a thin layer on the surface.
  • Try not to pour the mixture directly into the wood. Also, remember not to come in contact with the mixture as it contains turpentine and can be toxic. The oil itself can be damaging to your skin.
  • Rub the surface until the first coat looks even. Do not apply too much, but don’t use too little either. In short, don’t let the mixture create puddles on the surface or the floor, but also don’t rub too hard, so the mixture stays put.

Once you finish, the coat should be even and thick enough, so it is visible. Remember, only one coat. No need to reapply on the areas you already applied.

Let It Dry

Once you’ve finished covering the whole surface with the first coat, then you need to let it dry.

  • We recommend letting the surface dry for at least 30 minutes. This will harden the surface a little so you can then wipe it off with a soft lint-free cloth.
  • Now let the coating cure entirely for at least 24 hours. This should dry up the first coat and deliver a slight waterproofing effect. You can test it by sprinkling a little water over. Then wipe it off completely.

After 24 hours, you can wipe off the surface again – so you can continue applying the extra coats.

Apply a Second Coat

Once the first coat is cured, then you need to apply a second layer. Here, you will need to follow the same process as before and wait for the same amount of time for it to dry.

  • Apply the second layer and let it dry for 5 hours. The surface should look thicker now, and totally even.
  • Then sand the surface a little with a ball of steel wool. Be careful not to rub too much and get rid of the still wet second layer.

Then let it dry for at least 24 more hours.

Let It Cure

After 24 hours or a little more, you’ll see how the waterproof coats start to crystallize. This will leave a pretty surface.

You’ll know it is totally cured once you can pass your finger through the surface, and it will feel ultra-smooth.

This should happen in about 7 days or so. So, we recommend not exposing it to moisture if you want to prevent any damage to the waterproof coat.

Method 2: Waterproofing Wood with Wood Sealer

Using a wood sealer is yet another practical way for waterproofing wood. The advantages of wood sealers come from their outstanding waterproof capacity without leaving inconsistent surfaces behind. You get the smoothness and protection.

At the same time, you can recoat, re-sand, or simply paint the surface once you use a wood sealer. That’s why it is such an excellent option to go for.

Last but not least, waterproofing with a wood sealer offers another advantage: it dries up super-fast. In contrast with oils, sealants tend to be fast-drying, which allows you to use them in less than a day after application.

However, it is essential to remember that wood sealers can be highly toxic. So, you must take precautions if you want to prevent any unwanted damage. Wear your protective gear and work in a highly ventilated environment for a safer experience.

Without much further to say about them, here’s how to use wood sealers for waterproofing:

Get a Wood Sealer

First and foremost, make sure you get a wood sealer that genuinely fits your demands.

There are many types to go for, going from polyurethane to varnish, lacquer, and so on. We recommend varnish for its capacity to deliver a yellowing-free experience. It is also resistant to UV rays and can handle scratches and constant moisture. If you get marine varnish, then you get an even sturdier coat.

  • We recommend varnish for places that tend to be exposed to a lot of moisture.

Then you’ll find polyurethane. It offers one of the neatest and smoothest surfaces you can get. And sure enough, it provides high-gloss, low-gloss, soft sheen, and many other finishes as necessary. A polyurethane sealer is also utterly resistant and can last for years.

Lastly, you’ll find lacquer. This is the sturdiest of the three. Its scratch-resistant capacity and moisture resistance are outstanding. However, it tends to yellow over time, especially on light-colored woods. So, it is mostly recommended for darker woods.

  • Lacquer would be perfect for furniture and objects that you grab or move around consistently.

It is important to remember that all these sealers work differently. So, have these in mind before choosing:

  • They have specific purposes. Some of them are outdoor sealers, while others are floor sealers. Choose accordingly.
  • For bathrooms, there’s nothing better than marine sealers. This will probably be varnish, but you’re still free to pick whatever you prefer.
  • Always remember to check their application methods beforehand. You may want to be sure that you have all the tools as well as the environment necessary to do so.

Once you have the ideal wood sealer, then you’re ready to start applying it.

Prepare the Sealer

Before you apply anything, make sure you have the sealer ready to be applied. That means following the instructions on the bottle or container.

Usually, you just need to stir for a few minutes until the components mix thoroughly. Then you’ll be ready to spread it on the wood.

Apply a Coat

Now you can start setting up the sealer on the surface. We recommend using a paintbrush for the best results. This will make it a lot easier.

Here’s how to proceed:

  • Remove any remaining dust or debris on the wood surface. Use a damp cloth to clean it one last time before applying the sealer.
  • Now grab a paintbrush and start spreading the sealant on the wood surface. Remember to follow the wood grain as this will leave a neater result in the end.
  • Don’t let the product evaporate if you’re in a hot area. Remember that you need to be extra careful with these products as they may produce fumes and damage your lungs.

The first coat is now on the wood, and the piece is almost ready.

Let the Sealer Dry

Depending on the sealer you picked, you’ll have to let it dry.

  • Always follow the instructions that come with the sealer. Most sealers have a drying time of about 4 to 12 hours. You may need to let it dry for no less than 24 hours to make sure it is totally dry.
  • In the meantime, try to stay away from the surface you coated. Do not grab, touch, step over, or simply move.

After the time has passed, then you will get a shiny yet thin waterproofed surface to enjoy. But that’s not enough.

Clean the First Coat

Once the first coat dries up, you’re ready to clean it and get rid of the imperfections. For this, use a super-soft grit 320 sandpaper (or steel wool) and a damp cloth.

  • Before starting, read the product instructions. It will tell you exactly how to proceed.
  • If the sealer doesn’t have instructions, you will have to lightly sand the surface to get rid of the small inconsistencies.
  • Finish by cleaning with a damp cloth to get rid of the dry sealer residues behind.

Now, you’re ready to apply the second coat. You may not need to apply it in some cases.

Apply a Second Coat

The second coat will only be necessary if the wood piece is made of softwood and will be used continuously or exposed to moisture. But if it is made of hardwood and it’s not going to be exposed much, then a second coat may not be necessary.

Here’s how to apply it if you decide to:

  • Use the paintbrush to apply and spread around. This second coat will adhere less consistently to the wood as you will be applying it over another coat. So be careful not to spread too harshly.
  • While applying the second coat, focus on delivering an even finish. You should not let any inconsistency like over-applying or under spreading happen.

Once you’ve applied the second and last coat – you need to let the wood surface cure for some time.

Let It Cure

Curing a waterproof coat with sealant may take several days. But you shouldn’t worry too much.

  • Before placing the wood piece on its place or placing anything over it – make sure it is completely cured. We recommend waiting at least 24 hours. If you can let it cure for at least 48 hours, that would be even better.
  • Always follow the sealant instructions for better results. It will tell you how much time you need to wait for the curing process.
  • After it cures, then you’re ready to use it as you prefer. You may need to recoat after a year or so. Don’t hesitate to do it if you want to keep the wood waterproof and neat.

There’s nothing else to do, you’ve successfully applied the sealer to waterproof a wood surface in your bathroom.

Method 3: Waterproofing with Resin and Acetone

seal wood from water

Another way to waterproof wood finish is to use polyester resin and acetone.

This combination delivers one of the strongest results out there. The waterproof coats can last up to 5 years without problems. And sure enough, they will prevent even the slightest drop of moisture from getting into the wood.

Lastly, polyester resin alongside acetone dries up extremely fast (sometimes faster than wood sealers), so you get double the advantage. And because it is thin, the surface will end up super consistent and even, so there’s no need to sand.

Here’s how to proceed:

Get the Right Resin and Acetone

First and foremost, make sure you have the proper resin. You will have to pick between laminating resin and finishing resin.

The difference is that laminating resin lasts longer to dry up and often leaves a slightly softer surface. In contrast, finishing resin leaves a hard surface at first, while drying up a lot faster.

You could say that laminating resin is for the first few layers while finishing resins is for the last one. But you can go for either one you prefer. Or, if you want to do it correctly, then get both and laminate first.

Then you need the acetone. The whole purpose of acetone would be to thin up the mix a little. So, you won’t need much just enough so the resin is easy to apply on the wood surface.

Then you’re ready to prepare the mixture.

Create the Mix

Now with the resin on your hands, you need to mix it with the acetone. Here’s how:

  • Pour some of the thick resin in a bowl or bucket. Calculate what you’re going to need for the whole wood surface.
  • Then add some acetone. Don’t add too much at first, slowly drip some and start mixing. Stop pouring acetone when the mix is only a bit thicker than water. If the mixture gets too thin, then add some more resin accordingly.
  • You’ll have to prepare this mixture again for the second coat, so don’t prepare too much.

With the mixture ready, you’ll be set to apply it.

Apply the Resin

Here, you will need a paintbrush. A soft-bristled brush or a paint roller will also work, especially if they’re old, and you won’t use them again. Proceed like this:

  • Grab the instrument for application and damp it on the mixture. Then start spreading it around the surface.
  • The thin mixture will be very squishy, so be careful when applying. Try to cover your arms and overall skin, so it doesn’t touch you.
  • Once you’ve applied the resin, you can let it dry. We recommend letting it dry for at least 30 minutes.

Once the first coat dries up, you can proceed to add the next one.

Reapply a Few More Coats

After letting the first coat dry, then you need to reapply at least 5 more times. Because the mixture is pretty thin, you’ll need to apply the coat several times for the best results.

Here’s how:

  • Reapply by preparing more mixture. Remember, the resin should get almost as thin as water. But a little thicker than that will also do the job, especially if you’re using laminating resin.
  • Let each coat of resin dry for at least 30 minutes. When adding the next layers, be careful not to scrub the surface instead of spreading the mix. If you scrub too hard, you may damage the previous layers.

After the last layer, you can add some liquid wax, so it achieves a shiny effect. Then you will have to wait for it to cure.

Let It Cure

Once you’ve applied everything, then you should let it cure completely. This will harden up the whole surface.

  • Because of how thin it is, the resin mixture will cure in only 6 hours. You may want to leave it alone for 12 hours if you want to make sure that it cures completely.
  • Then test it to see if it works by spraying some water over it. The wood shouldn’t be affected at all, and the surface should repel the water instead.

If yes, then you’ve successfully waterproofed a wooden piece with resin and acetone.

Method 4: Waterproofing with Stain and Varnish

The last and best way to make waterproof wood furniture is to use stain and varnish. While varnish is actually a wood sealer, pairing it up with stain delivers a totally different effect – so we had to add it as an additional method.

This happens because varnish naturally leaves an outstandingly shiny effect. And with stain, it makes the wood look darker, which adds a uniquely beautiful effect.

The waterproof effect of varnish with stain is decent. And sure enough, they dry up outstandingly fast, which results in one of the most convenient methods.

Here’s how this works:

Get a Stain and Varnish

You’ll find several types of varnish and stain to get. So, we recommend searching correctly.

Some stains are interior-grade while others are for exteriors. Be sure to pick the right one according to the type of bathroom furniture or object you’re covering.

You may also want to pick between darker and lighter tones. It is up to you, depending on the finish color you want to achieve and the type of wood you’re covering. We usually recommend slightly darker tones than wood.

At the same time, you may not need to get a stain and varnish in different batches. You may find stain-sealant products out there that offer both products mixed already. This adds an extra touch of convenience, so you won't have to prepare the mixture eventually.

Prepare the Mixture (If Necessary)

Mixing the varnish with the stain is not too hard. Just follow this process:

  • Calculate in your head how much varnish you’ll need to cover the whole surface. Then pour it on a bucket or bowl.
  • Now add a few drops of stain. Don’t add too much as it could end up thinning the varnish and making it super hard to apply later. So be careful.
  • Mix the varnish and stain until the mix changes color entirely to something between the color of the varnish and the stain.

Now you’re ready to start applying the mix.

Apply the First Coat

Again, you’ll need a paintbrush or something of the like. This will help you apply the mixture more easily on the wooden surface.

  • Slowly dip the paintbrush on the mixture. Then start brushing it on the wood surface in an evenly way.
  • If it is a large surface, then try following the grain, so it looks better in the long run.

Once you’ve covered the whole surface, then you’ll need to let it dry. Four hours will be enough.

Remove the Excess

After the first coat has dried, then you should get rid of the excess and residues. Here’s how:

  • Find a piece of fine-grit sandpaper, 220 or greater. Then wipe it across the wooden surface softly, getting rid of inconsistencies and excess of varnish.
  • Leave the smoothest surface you can so the second coat can make the surface more even. This will also help it to stick easily.
  • Finish by cleaning with a slightly damp cloth. Try to get rid of any residues, dust, or debris on the surface.

Now you can apply the second coat.

Apply the Second Coat

The second coat will be a little more challenging to apply because the surface is already smooth. But it shouldn’t be too hard either.

  • Apply following the same process for the first coat. But this time, try being even more careful as not to spread the varnish too much. Try doing it super softly.
  • Let the second coat of stain dry for at least 5 hours afterward. If you can let it dry for a little more until the coat is not sticky anymore, then that’s even better.
  • After the second coat, you may apply a third one if you feel like it. This will add an even thicker waterproof layer, so you receive double the protection.

This coat will make the wood look totally different (probably darker) and will deliver a decent waterproof effect.

Let It Cure

After applying the final coat, you will need to let the whole surface dry for at least three (3) days. This will make it sturdy and make sure you can start using it without problems.

  • Test the surface by spraying some water over it after a few days. If the wood repels it, then you’ve successfully applied the waterproof coat into the wood.
  • If it is a floor or similar place with lots of traffic or constant friction, we recommend letting the varnish/stain dry for at least 5 up to 7 days.

Now you can enjoy the whole wooden surface with full waterproof capacity. You won’t be disappointed.

How to Protect Wood from Water in Bathroom

From learning how to seal the wood from water to preserving timber and making it last longer – protecting wood eventually becomes an essential thing to do. Here are a few ways to do that:

1. Oil and Lemon/Vinegar


It seems counterintuitive, but it works.

Adding standard cooking oil with some vinegar or lemon into a mixture will deliver one of the most wood-preserving liquids out there. Not only it protects against water damage, but they also preserve the wood and make it smell a lot better.

Especially if you have stains on the wood, this will be a perfect way to clean it as well. Just prepare some by adding oil and lemon with some vinegar into a sprayer and then pour it on the stained wood. Then wipe it off to get rid of the stains. It should work wonders.

2. Fix Issues at Once

Did a pipe break inside your bathroom? Then don’t let it stay broken for long.

Is your sink spraying water around too harshly? Then fix the water pressure, so it doesn’t spread that much.

Whatever the issue could be, make sure you can fix it before it’s too late. Letting most water issues in your bathroom happen for too long can be detrimental, especially to wood.

3. Waterproof Consistently

We showed you several methods to make waterproof wood that can last several years each. But still, you should waterproof again every once in a while.

A thin coat of waterproof material will be enough for every year or two. That will keep the waterproof capacity at max and prevent any type of water damage.

Frequently Asked Questions

Now that you’re done with the bathroom furniture waterproofing process, let's solve some of your doubts. Here are common questions most people make about waterproofing wood:

1. How Long does it Take for the Waterproof Coat to Cure?

Ans: It depends on the type of coat you’re using. Oils may require up to 14 days to cure completely. Sealers tend to cure in a day or two. Varnish requires up to a week. And resin with acetone cures in 24 hours or even less.

2. Will these Waterproof Methods Last?

Ans: Yes, they will last at least one year with constant use. We recommend recoating at least once every two years because of that, so you can keep the wood surfaces protected.

3. Can I use These Waterproofing Methods on Other Materials?

Ans: Yes. Polyester resin, for example, is a common alternative for covering concrete floors and other surfaces.

4. Are these Methods for Waterproofing Wood Safe?

Are these Methods for Waterproofing Wood Safe

They’re safe as long as you take the proper precautions. Use your safety glasses, gloves, boots, pants, and mask to stay safe.


If you got here, it means you’ve read the entire article, and it also means you’ve learned how to waterproof wood for bathroom.

And all that means it is time to take action. Pick the ideal method, get the materials, and start coating those wood surfaces now.

You won’t regret waterproofing your bathroom wooden furniture or surfaces. It will make everything last a long time!

You Might be Interested to Read:

  1. How to Get a Stylish Look Using Bath Mat Made of Wood?

10 thoughts on “How to Waterproof Wood for Bathroom: 4 Different Techniques”

  1. Hi there,

    Nice article but I’m still unsure what method to use for my bathroom.

    I have some reclaimed wood panels to use around a bath.
    I was going to stain them and then apply some teak oil over the stain.

    I was reading about teak oil and teak sealant.
    What is the difference and would I need to use both?

    Also, can I mix the stain with the oil/sealant?

    Thank in advance.

    1. Hello there,

      The difference is that teak oil is for looks and teak sealant is for protection. You can apply first the teak oil and then the teak sealant so you get both protection and looks. It is not a good idea to mix the stain with oil or sealer.

  2. What method is preferred is you are going to paint the sealed wood?
    Do you paint first or seal then paint?
    What type of paint?

      1. Thanks for your helpful advice here! Which kind of paint is best for a bathroom cupboard if I used marine varnish to seal it?

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