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.

Conclusion

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.

72 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!

    Thanks
    Rob

    • 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!

  12. Thanks so much for this. I’m looking for something to protect the wooden stand that my bathroom sink sits on. Can you recommend any specific products of stain sealant please?

    • Hi Lianne,

      Speaking of stain and sealer in one, I’ve only used Ready Seal which is only for exterior and sold only in gallons, sorry.

  13. Hi! I have read through all of the suggestions and still can’t decide which material to use. We bought a slab of unfinished Walnut for a counter top in the bathroom. If we use the tung oil, we should do at least 3-5 coats and let it cure for 30 days. This will make it waterproof, but will it make it shiny too? Do we then need to polyurethane over everything? Thank you so much!

    • Hi Morgan,

      The oil itself will protect the wood, you don’t need to apply polyurethane over the oil in most cases. Yes, the oil will add sheen to the wood, but how much, it depends on a certain product.

  14. William. My bathroom door is painted white and has started to show water bubbles effect it’s a wet room what’s the answer please Lena

  15. Hi Stewart,

    Thanks for sharing this article. I would like to build a vanity for my bathroom, a humid environment. Would I stain and seal each piece of wood before construction so they are totally waterproofed or build the cabinet first and then seal it?

    Thank you!

    Michael

    • Hi Michael,

      Obviously the first option will provide better protection but I don’t think that will have a great impact overall.

  16. Hi, I have an old piece of barn wood with large wormholes. Some big enough to that a pencil can go through. There are no worms – thank goodness. But the piece is unique and looks beautiful in its own way; like nature’s art. Do you think it will be ok inside the shower as a bench to hold a small tray with two soap dispensers? It will not be used for sitting. If yes, which method of waterproofing will you recommend, given that it will be getting wet. Thank you!

    • Hi Ray,

      It would be nice to use that piece of wood. Wood with holes, fissures, and cracks looks awesome in some cases. Usually, I recommend using sealers on pieces that are often in contact with water. But in you case, I recommend using an oil to enrich the color of your wooden piece.

  17. Hi William
    I wanted to paint and stencil my bathroom floor but i need to seal it what can i use that is cheap yet affective and gives a satin finish as well as waterproofing it.
    Even tho i hardly get water on my floor i still wanted something to seal the paint so nothing comes off or fades away.
    Thank you

    • Hi Usma,

      Oils and sealers hardly penetrate the paint. Instead, you need a finish that creates a protective layer over the wood. I recommend using Deft oil-based polyurethane which can be applied over the paint to protect it from damage and moisture.

  18. Hi William,

    As far as using the stain method, will shoe polish be an acceptable substitute? If so, how many coats should be applied and how much time should be given to drying and absorption after finish? Thanks in advance.

    • Hi Charlie,

      Nope, at least I’ve never done that and never heard of that method. So I wouldn’t recommend that, sorry.

  19. Hello,
    Remolding a 4′ shower stall and thinking of using a 2″ thick piece of Mahogany 3′ long as a bench seat. Do you think I can waterproof this wood enough so make it work. If so what would you reccommend to do this.

    • It is possible to waterproof this wood. There are several ways to waterproof wood: you can use an oil such as linseed oil, walnut oil, and tung oil. If you decide to take the oil route you can mix it with apple cider vinegar to obtain a more powerful waterproofing oil. If you don’t want to use oil, you can also use a waterproof wood sealer indoor or exterior. You can find this sealer at any hardware store. I would recommend this wood sealer.

  20. Hi,
    I’ve made a bath shelf and applied a sealant. As it is over water so often should I also apply a varnish please?

    • Applying a varnish would definitely help protect the wood even more from water damage. It isn’t necessary if you already have a sealant on it though. I would recommend using a varnish if you want more protection and don’t want to reapply the sealant as often.

  21. Hi, I’ve took out a3’ shower stall and replaced with a 6 piece 5’ tub shower. I put paneling around the top and in front of shower. What is the best thing to put on the paneling? It has a rough texture and the bathroom is in the basement. Didn’t wanna spend too much but want it to look good. Don’t know that it matters but it’s gray.

  22. Hi, i’m having a bathroom vanity built, the top will be made from reclaimed scaffold boards, the tap will be standing on the wood as will the bowl basin, what is the best waterproofing option for the wood?

    • I would use any waterproof sealer, varnish, or even polyurethane. I would recommend a sealer by Thompson’s or a spar varnish or something like that. If you decide to use polyurethane I would use something by Minwax.

  23. Hi William, I am installing a fiberglass shower in our cabin, the ceiling and walls above are cedar tongue and groove. What do you recommend sealing with? Thanks

    • Any interior wood sealer would work as well as a varnish or polyurethane. If you are to use a sealer I would recommend one by Thompson’s or Behr. If you are to use a varnish I would recommend a spar varnish and if you are to use polyurethane, I would use something by Minwax like this.

  24. William,
    I am putting a knotty pine bead board ceiling in my bathroom. I don’t want to stain the wood, as I like the natural look, but want to make sure it is protected from all the moisture. Would a sealer be best and if so what brand would you recommend? I would also like for it to have a nice satin or semi-gloss sheen to it.
    Thanks!!

  25. Hi William,

    I have an older crib that I want to turn into a indoor planter. I’d use a gardener’s pot inside of it, but water can drip through holes in the pot. What’s the best way to protect the crib from the excess moisture of the plants? Thanks!

  26. Hi William,

    I’m installing 3/4″ pine beadboard on my bathroom ceiling to include over the tiled shower. I’m aiming to keep the natural color of the wood. Would you recommend a sealer, and if so, do I cover each entire board, front, back and sides? Lastly, can you recommend a sealer for this job? Thank you! Dwane

  27. Hi William,
    I’m planning to make a really cool wooden bath shelf/tray that folds down from the wall. I plan to paint/stain/wax the wood to get a white finish (think limewax on pine) but not sure how to protect it from continuous water contact. Any ideas or products you would recommend?

    • I don’t recommend linseed oil over paint because it doesn’t form a hard durable film for protection. It’s only good when it soaks directly into the wood so the fibers can absorb it for the best results. Out of your two options, lacquer would be better but there’s a risk that lacquer might wrinkle the paint. If you are looking to protect the paint, I would recommend a Minwax polycrylic finish or a Minwax polyurethane finish.

  28. I have an antique bathroom sink vanity . It is distressed and I don’t want to change it. What can I use to waterproof the top of the vanity without changing the surface or color?

  29. Hi William,

    I inherited a kitchen sink surrounded by wood when I moved into my current flat (it’s beech looking wood). The constant washing of dishes has turned the surface of the wood a lighter, greyer colour, made the surface rough and mildew (I guess that’s what it is) starts to cover it in places- especially in nooks and crannies. I assume this is all from water damage. What do you advise I do and use to address the issue?

    Thanks so much,

    Sean

    • You can replace the wood if you want and seal it to protect it from water damage. If you don’t want to replace the wood, you can always sand it done until the surface looks smooth and clean and then seal it to protect it. Some good sealers are polyurethane by Minwax, spar urethane by Minwax, or a waterproof sealer by Thompson’s. All of these are great sealers but you will probably get the best protection from the spar urethane. If you are still scared water might get into the crack between the wood you can always put silicone around the edges after you seal the wood to cover the cracks. If you decide to use silicone, I would suggest using this silicone by GE.

  30. Thanks a million William, that was really helpful.

    Sorry to ask more questions- I am new to D.I.Y!

    I believe after sanding the area around the kitchen sink i’ll need to lift the colour of the wood before sealing it (It is quite dry/pale/washed-out looking) compared to other areas. I was thinking of using tung oil to bring the colour back. Then making it uber waterproof with a sealer. A few questions though:

    1. I know you generally either use tung oil or sealers but we wash so many dishes so frequently the area is always covered in water and collects in pools at times- hence the desire to go all out on water proofing! is this even possible? Will the sealer take if I have already used tung oil? Or is this just a ridiculous idea and I just need to use tung oil to restore the look of the wood and make it 100% water-proof?

    2. It sounds like it could take weeks after applying tung oil (in particular) but also the sealer before the wood is internally, fully dry. Is this right? If yes, in this time do I really need to keep the area 100% water-free? It’s literally the kitchen sink so used to wash dishes, prepare food, etc. I think I would struggle to find an alternative place to do all these things for such a long time.

    Thanks a lot,

    Sean

    • Yes, it is possible to seal over tung oil. Just make sure the tung oil is completely dry before applying the sealer for the best results and to make sure both products are effective. I would suggest trying to keep the wood around your kitchen sink as dry as possible for the best results but this whole process shouldn’t take that long.
      The only thing that takes long is drying. To protect the wood while you are washing dishes you can always cover it with plastic drop cloth and tape it to the side so no water can get through, and then take it off when you are done so the wood can continue to dry. Hopefully, this helps!

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