How to Waterproof Wood for Bathroom

How to Waterproof Wood for Bathroom

bathroom woodWhen the wood you use in designing the floor of your bathroom or the vanity of your sink and dresser is constantly greeted with moisture, deterioration is imminent.

Since this is the sad reality on the ground, how then do you protect the wood from moisture? How do you retain this beautiful wooden floor finish without incurring the wrath of the waters and so the big question lingers – How to waterproof wood for a bathroom to avoid the damage being caused by moisture ever-present in your bathroom?

Well, the good news is; this article will answer that boiling question. All you need to do now is to continue reading.

How to Waterproof Wood for Bathroom

There are three fail-proof methods you can use to waterproof your wood in a bathroom world where water rules.

But you need to know this first: there’s a thin line between waterproof and water-resistant woods.

So when next you are assured that a certain piece of wood is water-resistant, it means it can resist water to a certain limit but at the end, it will finally bend to the resilient forces of water. On the other hand, a waterproofed wood means that the wood is forever protected from the forces of water.

That’s the angle I’ll be showing you in this article. You waterproof your wood forever with three methods below. Three fantastic options and once the choice for you to make. We’ve had much ado already on introductions, so let’s begin with the first method.

First Method: Waterproofing Wood with Oil

There are three oil options you can use to waterproof your wood. There is the linseed oil, walnut oil and the tung oil. Whichever oil you decide to use, the following procedures will help you waterproof your wooden bathroom decor and keep the waters at their bay.

  1. Mix the oil with either turpentine or apple cider vinegar to obtain a more powerful waterproofing oil. Ensure you stir thoroughly. This isn’t a must as you can still use the oil singly.
  2. Prepare the wood surface by using sandpaper to smoothen rough surfaces and edges. Rough surfaces will become visibly evident and appear distasteful when you are through with the oiling, that’s why this step is important.
  3. Dip a soft-bristle brush into the oil (whether it’s the mixture or single oil) and apply thoroughly around the wood leaving no surfaces and edges untouched.
  4. Allow the surface and edges of the wood a little time to absorb the oil this will enable you to identify untouched areas and then you can do the needful by reapplying on those areas.
  5. Let the wood to absorb the oil again and then clean off oil residues with a clean dry rag.
  6. Allow the wood time to dry. Oil mixtures dry faster than single oils. Drying time could take a couple of hours or even half a day if you using a single oil.
  7. After you’ve allowed the wood to dry, you can then reapply the oil again on the dried wood surface if you’ve got more to ensure it’s heavily finished and waterproofed.

Other Things to Note about using Oils

  • Although some oils come mixed with other chemicals, you can do the mixture yourself and freely experiment as you continue with the process after a long while.
  • If you are purchasing an already blended oil, then know it has three parts namely: the linseed or tung oil, mineral spirit, and polyurethane. The mineral spirit and polyurethane are added to the chief oil (Tung or Linseed) alongside the turpentine and stirred thoroughly before application.
  • You can obtain the linseed oil naturally and boil before application. You can always find ready-mades in DIY markets any day.
  • If you desire a thicker combination, keep the mineral spirit addition minimal.
  • Addition of polyurethane can increase or reduce the drying time. Add more if you want quicker drying time. Add less if you want extra time to work more before it begins to dry off.
  • After application and drying, give the wood some time to settle and absorb what it had just received. Hours won’t be enough. A couple days would do. Don’t ever use immediately after the finishing.
Oily rags are combustible so while you rag away oil residues for re-application, remember to wash the rags with soap and water.

Second Method:  Using Sealants for Wood Waterproofing

moisture-and-woodThis method entails using sealants to waterproof woods. The steps for application are almost the same as that of oils.

The only deviations here are that, you don’t necessarily have to mix the sealers with any other natural or synthetic chemicals. But you have to wipe the wood dry, sandpaper it and that does it for the preparations before application. You can apply the sealer afterwards by either spraying or using a brush. Allow to dry after the spraying or application with a brush is over. Then apply two more times to ensure your wood is well guarded against water.

Other Things to Note about Using Sealants

  • To obtain perfect results, apply sealants at room temperature, temperature above this can affect the potency of the sealant.
  • Do not stir or shake sealants. They are not like other liquids that require vigorous shaking to enable the content to circulate all-round the container.
  • They dry faster than oils, but you still have to allow the air to freely passage anywhere the application is being done.
  • After application and drying, give the wood ample time to absorb the protection it has received before you start using it. Any time from 3 days would be enough.

Third Method: Waterproofing Wood with Stain and Sealer

wood-stainThis happens to be the most efficient and classy method of waterproofing wood for bathroom. Why? Because you can choose to use stains alone or you can do powerful stain-sealant combo. These stains when applied are translucent. Lighter stains come with more oil. They are best used for interior woods like your bathroom which is the center of everything detailed here.

The application process isn’t anything different from the other two. Wipe the wood dry, sand to smoothen the surface and limit imperfections on the job and then apply with a brush. Allow to dry, remove residues with a clean dry rag and reapply up to two or three times afterwards for a thorough finish. This applies to both stains and stain-sealant combinations.

Why Stain-Sealant Combination is the Ultimate

Stain-sealant waterproofing combinations are the best when it comes to effective waterproofing and addition of styles to the job.

They come in a variety of colors. That you want to finish your wood for waterproofing doesn’t mean it should lose its aesthetic appeal.

These colors are products of color pigments with the inclusion of binders like oils, water or alkyls-based binders.

Stain-sealants hardly build up on the surface, they are absorbed into the wood as soon as they are applied, so it’s needless to wipe off residues because they would have evaporated before you do so. Akyl-based stains, however, leave residues on the wood surface.

Other Things to Note about Stains and Stain-Sealant Combinations  

  • If however, you intend using them for exterior woods, you need to find exterior grade stain for that purpose and you would have to keep up with waterproofing at least after every two-year interval.
  • Stain-sealant combos with color pigments and binders that are oil-based are best recommended for interior woods just like the one you would be using in your bathroom. But their alkyl-based counterparts in spite of the build-up they leave on the wood surface offer a more aesthetic appeal to interior woods.


Although they appear rustic and yes they truly are rustic and you can call them antiquated, no doubts, but they make the finest of furniture and cabinetry. These natural building materials called woods need protection from moisture. Wood and moisture can never harmonize, not now, maybe in the nearest future.

Your choice of the method here is dependent on the budget you’ve set aside for the project. If it’s a big project that involves the entire house you can go for the last method; stain-sealant, which offers more efficiency and saves time. Remember to take some thumb rule precautions like using gloves. You are dealing with chemicals and not just liquids.

Wash your hands after you are done with the entire process, including the tools you used. Don’t forget to keep out of reach of children.

Water shouldn’t be a reason why you can’t have that rustic goodness on the floor of your bathroom, the vanity of your sin or dresser or anywhere around your bathroom you intend using the woods. This is why you need to arm yourself with this information on how to waterproof wood for bathroom.

32 thoughts on “How to Waterproof Wood for Bathroom”

  1. William, I am designing a custom wood countertop insert for my kitchen. It will hold a bamboo cutting board, with a recessed scrap bin at one side. I really want to install a wall mounted cold water tap above it for washing vegetables etc (the scrap bin will have a drain) Do you have any other suggestions for treating the wood other than what you have outlined here? Thanks for the help!

    • Hi Greg.

      There are also varnishes, but they’re mostly for exterior use. I think sealer is the best option to waterproof wood since it penetrates into pores, it’s much better than finishes that form kind of topcoat. What’s wrong with sealing or oiling wood?

  2. I bought an antique dresser and want to use it for bathroom vanity with a vessel sink on it. What would be the best way to waterproof it.

  3. Hi William

    Great article! Which method would you recommend for a bathroom window sill, made of oak? I have it sanded and ready to treat, but not sure now which one!


    • Hello Rob.

      I think oil would be a good choice here since the window sill won’t have direct contact with water that often. Furthermore, an oil will enhance the natural color of oak.

  4. We are making a vanity with a vessel sink from a live edge piece of wood. We have already stained it, can an oil be used over the stain or do we need a polyurethane?

    • Hello Susan.

      Stained wood can be oiled, but it’s better to use polyurethane instead of oil since both stains and oils penetrate the surface of the wood so after the stain is applied oil isn’t that effective.

    • Hi Sharon.

      It’s senseless since sealer has to penetrate the wood pores. Polyurethanes and varnishes block wood pores creating a topcoat layer. Furthermore, varnishes are just an alternative for sealers.

  5. Hello,
    I want to make some pine wood shelves to go above my bathroom sink. They will come in contact with water and general moisture once placed. I want to know what would be best waterproofing option for me? Can I strain them and then waterproof them with oil instead of a sealant?

    Thank you in advance!

    • Hello Savaira.

      Strain? Did you mean stain? 🙂 Yes, you can stain them before waterproofing. I personally think that the sealer is better than oil for wood that is constantly in contact with moisture and water. But oil can be used too, keep in mind that oils need to be reapplied more in comparison to sealers.

  6. I have a 12’ Walnut slab as a bar top but am unsure how I should finish it so that it holds up to home bar abuse. Any recommendations?

  7. Hi, I have wooden panelling on the lower half of my bathroom walls with tiles on top. I want to waterproof the wood around the bath so it could also be used as a shower, what products would you suggest to be most efficient at keeping the wood safe from rotting with time?

  8. Hi William,
    We really would like to put wood cladding in our bathroom and paint. But having trouble working out the best way to protect the wood. Please help!! Thanks 🤗

    • Hi Jenni.

      Since you’re going to paint cladding first I recommend using varnish, namely TotalBoat. Don’t worry, it’s suitable for interior wood too. Varnish provides great protection from moisture and doesn’t need to penetrate the wood, unlike oils and sealers that would be useless over the paint.

  9. Hi, I’m putting a bathroom in a old farm house and there is a beam we want to leave exposed that would be in the shower, what method in this article is best, sealer or stain sealer?

    • Hi Brenda.

      Besides sealing, a stain sealer will change the color of the beam since stains are designed to dye the wood. Choose a sealer if the only thing you need is to protect the beam from moisture.

  10. Hi William

    We are using sawn oak that has been seasoned for a couple of years already as a work top for our sink in the bathroom. It will need to be waterproof. We haven’t done anything yet than cut it and sand it. We have removed the bark but kept the wane edge. We would love to keep it looking very natural and rustic so would appreciate some advice on how to waterproof it properly. Thanks! Jemma

    • Hi Jemma.

      I recommend using oil since it enriches the natural beauty of the wood unlike other finishes such as sealers.

  11. William, I have a new piece of finished furniture (dining buffet) that I want to use as a bathroom vanity with vessel sinks. It sounds like the Sunnyside oil is the best option. I don’t want the finish to look different than it does now. Can you tell me how the finish will change with this oil applied? How many coats would you recommend? Thank you!

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