Using wood in a bathroom requires some thought to prevent pooled water from leaving water stains or high humidity levels causing decay. If you don’t use the correct finishes, your wood will incur damage, mold, and rot, which can be bad for your health, unpleasant to look at, and costly to fix. In this article, we’ll discuss several methods to waterproof wood for a bathroom to ensure you get the maximum life from your decor.
Despite the huge variety of products on the market, there are three principal methods of making wood resistant to water.
- Surface sealants – this envelope the wood in a plastic-like coating that prevents water ingress.
- Oils – we know that oil and water don’t mix and that oil soaks into the timber, so when used as a surface finish, oils nourish the timber while repelling water.
- Nano-sealants – These sealants work at a microscopic level, penetrating deeply into the wood’s pores to block capillaries, preventing moisture ingress while allowing the wood to breathe.
Some products can use all three methods to provide the desired protection. So how do you choose? Looks, cost, and durability are three factors driving product selection, so let’s look at each wood treatment method and discuss its pros and cons.
Surface Sealants for Waterproofing Wood
You’ll hear several names used to describe these products, including polyurethane, varnish, lacquer, and shellac. The difference between these products is due to the resins and solvents used in their manufacture. Therefore, each offers different advantages and benefits based on its constituent parts.
Shellac
Shellac is a natural product made by mixing alcohol with the resin secreted onto trees by the female lac bug, sold in flakes. Comprising various acids and waxes, it provides a natural stain, sealant, and high-gloss varnish. Primarily used on fine furniture, antiques, and interior woodwork.
Pros
- Non-toxic -Food safe
- Dries quickly – Is easily repaired
- Adds a warm amber color to wood – Applies to almost all surfaces
- Most finishes can be applied over shellac
Cons
- Not particularly waterproof – Can be damaged by heat and chemicals
Lacquer
Modern lacquer comprises cellulose treated with nitric and sulfuric acid and uses plasticizers, pigments, and other resins (such as acrylic) to enhance specific properties like durability, sheen, or color. Commonly applied by spray and used on indoor furniture.
Pros
- A reasonable level of water resistance, as long as exposure is not prolonged
- Dries very quickly
- Durable, scratch-resistant finish
Cons
- Degrades or clouds on prolonged exposure to water
- High volatile organic compounds (VOCs)
- Can yellow over time
- Not resistant to UV
Polyurethane
Polyurethane is a synthetic resin made by reacting a polyol with a diisocyanate or a polymeric isocyanate in the presence of certain catalysts and additives. Manufacturers include additives to modify properties like flow characteristics, drying time, durability, and resistance to UV light. You can buy oil-based or water-based polyurethane. It is commonly used for floors, kitchens, bathrooms, and outdoor furniture.
Pros
- Forms a hard, plastic-like layer over wood, sealing it from moisture and water – damage
- Flexible finish
- Superior waterproofing capabilities
- Very durable
- Resistant to chemicals and heat
- It can be purchased in various finishes, from matte to glossy.
- Water-based polyurethane dries quickly to a clear finish with fewer odors
- Oil-based polyurethane can last ten years before a reapplication is required
Cons
- Oil-based polyurethane can yellow over time, has more odors, and takes longer to dry
Varnish
Varnishes can be natural or synthetic, combining wood oils, resins, and solvents. The inclusion of oil nourishes wood and helps repel water. Varnish dries through the oxidation and polymerization of the oils, meaning it cures by reacting with oxygen in the air. It is often used for outdoor projects and surfaces exposed to water, like boats and outdoor furniture.
Pros
- Highly resistant to water and moisture
- Provides a hard, durable finish
- Adds a warm amber hue to the wood
Cons
- It can be hard to apply it smoothly
- Takes longer to dry than shellac and lacquer
Applying Surface Sealants To Wood
- Lacquer is normally applied by spray, while polyurethane and shellac can be applied with a brush.
- Ensure the wood is sanded smooth, all sanding dust is removed from the area, and the wood is dry.
- Apply several thin coats in a well-ventilated room, allowing each coat to dry before reapplying.
- Lightly sand between coats with fine sandpaper.
- Remember to observe the manufacturer’s recommended drying times.
Oils for Waterproofing Wood
Two types of oils are used in woodwork: drying and non-drying. If we want reasonably persistent water protection, we need a drying oil that hardens to a tough surface film in contact with air. Let’s be clear, however: oils are not as good at water protection as sealants, but they do provide some protection while nourishing the wood.
When drying oils are exposed to oxygen, the hardening process occurs through polymerization or crosslinking. Drying oils that are commonly available are tung oil, linseed oil, and walnut oil. You’ll also see people quoting products like Danish Oil and Teak Oil; these are not pure oils but mixtures of the previously mentioned drying oils with some additives; however, they’re readily available, and some are good products, so we’ll include these in our discussion. Let’s look at the properties, pros, and cons.
Tung oil
Tung oil is produced by pressing the seed from the nut of the tung tree. The tree is of Chinese origin and has been used for centuries to produce oil, originally to waterproof ships’ hulls. Raw tung oil can produce a wrinkled finish as it dries, but today, the oil is heated during manufacture to increase its viscosity, prevent the wrinkling effect, and improve its film-forming characteristics.
Pros
- The best water resistance of the drying oils
- Finishes can be satin through to glossy, depending on thinning
- Has a slight golden tint
- Dries very hard
- Less prone to mold than linseed oil
Cons
- Takes 1 to 4 weeks to cure, depending on the temperature
Linseed oil
Linseed oil is manufactured by pressing dry, ripened flax seeds. Its edible form is known as flaxseed or raw linseed oil. However, it does not dry well in this state. To be useful for wood application, raw linseed oil is mixed with linseed oil that has been boiled to undergo chemical change, and drying agents are added. Boiled linseed oil is not edible or food-safe.
Pros
- Light yellow or amber color
- Slow drying
- Low shrinkage
Cons
- Not very resistant to water
- Easily scratched
- Known to mildew or turn black over time when in the presence of moisture
Walnut oil
Pressing walnuts produces walnut oil, a lightly colored and scented food oil. Like all food oils, pure walnut oil will go rancid over time, so the oil we use on wood is heat-treated to remove the proteins, alter the chemical characteristics to prevent deterioration and make the oil hard-drying.
Pros
- Fast curing – half the time of tung oil
- Thin, so it deeply penetrates the wood fibers
- Foodsafe for wooden objects used in food preparation
- Good water resistance – better than linseed oil and just behind tung oil
- Often mixed with beeswax for finishing timber
Cons
- You’ll use more due to its low viscosity
Danish oil
Danish oil is a combination of oils and varnish. There is no specific recipe, so each manufacturer uses their own mixture and additives. If you wish to mix your own, a common combination is one-third varnish, and the balance is a mix of linseed oil and tung oil. With Danish oil, you get the best of both worlds by nourishing the wood while getting greater water resistance due to the varnish. You’ll see some woodworkers claiming Danish oil is food-safe. However, that is incorrect if it has boiled linseed oil as a constituent.
Pros
- Better water resistance than pure drying oils due to the varnish
- Reasonably quick drying time
- Easily applied
- Matte or low-sheen finish
Cons
- Scratches easily
- Not food safe due to the linseed oil
Teak oil
Teak oil is another hybrid oil that’s even harder to pin down than Danish oil. A great study was done some years ago by a woodworker and boatbuilder who analyzed many proprietary products on the market at the time; he found teak oil to be so varied in ingredients as to make the name meaningless. Different manufacturers used either wax and turpentine, pure linseed oil, pure tung oil, a mix of mineral oil and dehydrated castor oil, pure varnish, or an oil and varnish blend. This variety makes it impossible to make a statement about the efficacy or otherwise of teak oil when we don’t know what it may contain. You’ll need to be guided by the manufacturer’s claims.
Pros
- Depends entirely on what your particular brand contains
- If primarily oils or waxes, it nourishes the wood
Cons
- No certainty on whether it is water-resistant or food-safe
Applying Drying Oils To Wood
- Caution must be exercised when using drying oils, as oil-soaked rags may spontaneously ignite as they dry due to the heat generated by an exothermic reaction with air. Wash them in soapy water and hang them out to dry individually.
- Apply to properly sanded wood with a natural bristle paintbrush.
- Allow it to dry before lightly sanding it with fine sandpaper, then apply another coat.
- Apply as many coats as you need to get the desired finish and coverage.
Nano-sealants for Waterproofing Wood
This type of sealant has been used in the construction industry for years but is relatively new to the retail market; however, it’s catching on fast. The principal behind nano-sealants is using chemicals like silane, siloxane, or silicone as a waterproofing ingredient.
These products have small molecular structures that penetrate the gaps and capillaries in wood or other substances and fully or partially block them. They prevent the large water molecules from entering, permitting smaller water vapor molecules within the timber to evaporate. Engineers refer to this as a breathable membrane. Some products combine these nano-sealants with polyurethane or varnish to get a double effect, sealing the wood’s pores and the surface.
Pros
- Highly water resistant
- Don’t yellow
- Natural finish
- Environmentally friendly
Cons
- Some products can be costly
- Not UV resistant
Applying Nano Sealants To Wood
- Ensure the wood surface is clean and dry
- Apply the sealant by spraying until you get pooling or run-off
- If some areas dry more quickly than others, apply a second light coat
- The surface is normally touch dry in 1 hour, although full cure takes a week.
A Note On Stain Sealants
You’ll often read advice that shows stain sealants as a fourth waterproofing method. It isn’t. As the name suggests, it’s simply a sealant with some pigment added to apply color to the wood. Stain adds no waterproofing capabilities, although the color can provide limited UV protection. Stain sealants are ideal if you want to seal your wood and apply some color simultaneously. Otherwise, you can stain the wood separately and then apply your chosen sealant over the top.
The pros and cons of stain sealant are largely related to the type of sealant being used, with the added bonus of applying a desired color at the same time as you seal, saving you some time.
Conclusion
It’s worth noting that while we speak about waterproofing wood, no surface covering or sealant is truly waterproof without ongoing maintenance. It degrades in sunlight, gets scratched, or the wood swells, moves, and cracks. Whatever surface coating you select, there will come a time when you will need to maintain it by lightly sanding it back and reapplying the surface finish.
I trust the information in this article has helped you decide the surface finish best suited to your bathroom and provided a finish that protects your wood and suits your decor.
Frequently Asked Questions
Wood can be used in bathroom or showers as long as sealers applied to it is maintained. If wood is taken care of, it will last a long time.
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Yes, waterproofing wood for the shower can be achieved by using sealers.
They’re usually a clear/transparent finish that goes on the outside of the wood. Sealants such as polyurethane, varnish, and lacquer give excellent waterproofing and can be used for showers.
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Be sure to ventilate the bathroom well with extractor fans or windows. Clean up any spills and wipe down moist surfaces to accelerate drying. Reapply the sealant regularly to maintain the protection level.
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There are different methods to waterproof bathroom wood but using a sealant is one of the best methods to do so.
Sealers can waterproof the wood, they can also prevent wooden surfaces from getting scratched. They are often a clear/transparent finish that coats the wood’s exterior surface.
Sealants such as polyurethane, varnish, and lacquer give excellent waterproofing. They’re brushed or sprayed over sanded, clean wood, then softly re-sanded and re-coated when they’ve dried fully. They offer high moisture resistance compared to the oil finish.
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Yes, it’s designed for boats, and it contains oils to nourish the wood and UV blockers to protect deterioration from the sun’s rays. However, it’s a great product for use in humid environments like a bathroom.
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One of the best sealers for wood in the bathroom is spar-urethane.
It’s frequently used on submerged wood, like boat hulls. This particular finish is intended to endure the weather on the hardwood poles that hold a boat’s sails, commonly known as the ship’s spars.
Spar urethane was designed to endure difficult circumstances and preserve the ship’s spars since this piece of wood must withstand severe wetness and wind.
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Be sure to seal all joints with a bathroom sealant or caulk, and where possible, select wood that is naturally durable, like teak, cedar, or mahogany.
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One of the best wood for bathrooms showers is teak.
Teak is one of the few hardwoods that can withstand damp circumstances due to its low shrinkage in changing weather and great resistance to rot, fungus, and mildew. It has natural anti-slip qualities and is remains the most often used material for boat decking today.
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Hey!
Great article, very helpful!
I just wanted a little advice on which varnish to use if possible?
we bought three wooden doors for our flat and have stained them with exterior Sadolin stain (we were told it’d be the hardiest and we liked the colour so went with it). One of the doors is for the bathroom so I wanted to put a varnish on top to protect them and have been looking into polyurethane. Would an exterior varnish be recommended to make the finish even hardier and more protected from moisture? As the ventilation in the bathroom is not very good so there will be a lot of moisture. And if so, is there a brand/ product in particular you’d reccommend? This is my first time doing anything like this so any advice you have is amazing! Thank you so much! 🙂
Hi Jess,
Exterior polyurethanes generally have a UV blocker added to protect the underlying timber. You probably won’t need that inside. I suggest using a water-based polyurethane so that it dries quickly, and choose the finish of your choice, either matte, satin, or gloss. You can’t go wrong with a product from Minwax, Varathane, or General Finishes – they’re all solid brands.
Our house is 118 years old and is made of tongue and groove pine. The walls and floors. We’re remodeling the bathroom and have some tongue and groove boards I want to use for the bathroom floor. Previously these boards were wallpapered but no glue was used on the wood. How can I waterproof the floors so they will match the rest of the floors in my house. What’s the best solution?
Hi Debbie,
I’d choose a sealant if you’re looking for maximum waterproofing and minimum work. A good quality matte polyurethane will seal the wood with a protective coating. If you use a water-based product, it dries quickly, and the fumes rapidly dissipate. Here’s a link. You don’t say if the other floors in the house are stained, but you can get polyurethanes that provide a stain sealer combination, or you can stain first and then seal.
Hi William!
Your web page is incredible, thank you!
I have an old wash stand with a hole in the top for a basin and jug (which I don’t want).
I have a piece of bamboo that has been cut to size with edges finished to place on the top!
I want to waterproof this as it’s going in a bathroom. After reading your article Im leaning toward the stain sealer option… is this ok for bamboo?
Thanks,
Emme
Hi Emme,
Thank you for the compliment; I’m glad you like my site. Yes, stain sealer is fine for bamboo – choose the one you like. I recommend the Thompson’s range as they do transparent, semi-transparent, or solid color stain sealers, with a range of colors to choose. Take a look at their products here.
I’m going to use cedar siding shingles on my bathroom shower walls , should I pre seal them before install or just seal it all after install and what sealant product would work best .
Hi Skip,
I always pre-seal wood before I fit it, then give a final coat to external surfaces to fill any openings created by fastenings. Have a look at this article I wrote in 2022 – it covers a range of sealers that would be suitable. I like the Thompson’s and Seal-Once products, but choose one to suit your budget.
Hi Derrick, I bought this acacia wood bath tray from The Futon Company about 3 years ago. It seems to have faded and dried out out in areas. Can you what is the best treatment to make it like new again (as in the ebay listing here), waterproof and resisatnt to long soaks in a steaming bathroom :-).?
https://www.ebay.co.uk/itm/204209578892?var=0&mkevt=1&mkcid=1&mkrid=710-53481-19255-0&campid=5338749401&toolid=20006&customid=GB_11700_204209578892.144241308393~1872316465195-g_EAIaIQobChMI2rPw6vjW_AIVEOrtCh1mGQ69EAYYASABEgLCjfD_BwE
Many thanks,
Tim
Hi Tim,
While acacia is a great wood for steamy bathrooms due to its moisture and bacteria-resisting properties, it will fade and warp if not protected every so often. I’m a great fan of Tung Oil as it brings back the wood’s natural color without changing it. I’d scrub the tray well to clean it and let it dry completely before applying the oil.
I want a sealant I can apply to a plywood wall prior to tiling
I dont mind if its clear or coloured as long as it seals the wood
I dont mind if its a spray or a brush applying it
I just want it to seal the ply
Hi Derrick,
You have two choices. There is an all-in-one wood sealer using siloxane, silane, and silicone. It’s clear and very effective, although some products are not cheap. Otherwise, use an oil-based polyurethane if you’re looking for effective and cheap. However, ensure the poly is fully cured – not dry – cured, before lightly sanding to scuff the surface before applying the tile adhesive. The curing of oil-based poly can take weeks. Be sure to read the instructions.
Two links follow to give you an idea of what I’m suggesting and their cost:
Seal-Once Nano+Poly Penetrating Wood Sealer – https://geni.us/gcV8j9
Varathane 6041H Oil-Based Ultimate Polyurethane – https://geni.us/WpC91R
Hi, Thanks for all your info. It’s so interesting in so many ways.
We just put in a new tub and tub surround. I’d like to put Caribbean heart pine above the surround on all three sides up to the 10′ ceiling. We have the CHP for flooring in our house and finished it with Monocoat Rubio. Can we use that above the tub? Or something else? The window trim and baseboard will also be the CHP.
Thank you!!!
Hi David and Elise.
I have no personal experience with Monocoat. I note that Monocoat suggests their Oil Plus 2C product for bathrooms, so if that’s the one you’re using, you should be good to go. However, note they say the product is water resistant, not waterproof. If the area gets very wet and stays that way for a while, you may prefer to use a film-forming product.
One product I’ve taken a shine to is the Seal Once range of Nano+Poly sealers. They seal the wood fibers and form a film on top of the wood, so their ability to seal out water is comprehensive, with a warranty to seal out water on vertical surfaces for up to ten years. You can choose between a clear matte, or a tinted product. Heres a link to their website: https://seal-once.com/nanopoly-premium-wood-sealer/
Hi there, this has been by far the most helpful information on the internet in my searches so far!!
There is aot of info here which I am taking in, but I’d be grateful if you could advise me..:
I am doing a van conversion and have an unfinished shower room. The walls are made of ply. Rather than sticking pvc on top and sealing all joins, which could add a lot of weight and cost, I would like to find the best way to waterproof the ply itself. This way the seals and corners stay visible in case of spotting and fixing future leaky troubles. My budget is small… Is linseed oil enough to waterproof my tiny ply box 55cm base shower room? I have a window in there for ventilation but I am also concerned that certain products could release harmful chemical fumes into my tiny home.
Thanks for your help x
Hi Maddie, and thanks for the kind words – these are the kind of comments that keep me motivated to deliver this service 🙂
As for your question: no, unfortunately, linseed oil won’t do the trick. While some people swear by it, tests have shown that moisture passes through it into the timber. It can also go moldy.
I’d be tempted to use a hybrid product that blocks the capillaries of the wood and adds a surface film simultaneously. I’m a bit of a fan of the SealOnce Nano+Poly Premium Wood Sealer, which you can view at this link.
However, I’d advise sealing the joins and corners with some form of sealant; otherwise, you’ll pour water behind the ply each time you shower.
Hi.. I’m putting a skirting board and tongue and groove on the back wall of my bathroom where the lavatory is. I guess I need to seal it but wanted to paint it white using regular silk paint to match the rest of the room. Can you paint over stain sealants?
Hi, Alan. The answer is a qualified yes. I say qualified because I don’t know the sealer type you’re using or the top coat paint base. You can generally paint over wood sealers if they are fully cured (note I said cured, not dried), and you give the surface a light scuff with 220-grit sandpaper. Some swear by using a primer first before applying the paint.
My foolproof, go-to answer when there’s any sliver of doubt is to use shellac as a barrier coat between the sealer and the paint. Shellac sticks to everything, and everything sticks to shellac. I hope that helps.
Can I ask how the sealant is cured? Many thanks
Hi Jacq,
Curing occurs over time. Most sealers dry quite quickly, in a matter of a day or two, but can take up to a month to fully cure. When they are cured, they’re at maximum hardness and are inert. Each sealer will have different curing times, and the manufacturer’s data will usually give the time to allow for curing.
Thank you, William for the great information! I am going to convert a gorgeous antique dresser that my mom refinished about 50 years ago. It was in my grandmother’s boarding house for a good 40 years prior! Because it was refinished 50 years ago and has had Pledge applied occasionally over the years, do I still need to lightly sand the wood before applying whichever sealer I choose to use? Also, I thought I might put a sheet of plexiglass over the wood. I am using a raised vessel sink on this piece.
Thank you for any advise you can offer!
Charesse
Hi, Charesse. Much depends on how well your mom refinished the wood previously.
If the silicone spray hasn’t soaked into the wood, but simply stayed on the surface, you might get away with scrubbing the surface with denatured alcohol, or isopropyl alcohol. I’d go over it three times with clean rags each time.
If the silicone has soaked in, you have two options, sand it as you suggested, or use the alcohol method before applying a few coats of shellac (no wax). Shellac goes over just about anything, and anything goes over shellac. You can then apply your sealer. The perspex will work, but there’s the aesthetics to consider.
The best answer is to immediately dry the surface when water gets on it – don’t let it sit. It doesn’t matter what surface finish you use; if you let moisture sit on the surface, you’ll get a degree of blushing.
Thank you so very much for the information!
This is brilliant! I’ve recently bought a corona pine sideboard to go into my bathroom to be converted into a vanity with a sink. I’ve bought a countertop sink to go on top. What do think would be the best product to use to make it waterproof and if possible, can you recommend one, please
Thanks
Sam
Hi, Sam. I swear by polyurethane in a bathroom.
You can use hardening oils and waxes, but they’re very labor-intensive, requiring frequent reapplication. Select a matte or satin polyurethane or even a spar varnish that includes some oil. Water-based products are more expensive but dry quickly. Oil-based products are cheap, take longer to dry, but last a lot longer.
I’ll suggest one water-based poly, one oil-based, and a spar varnish for you to choose between:
Water Based Poly – https://geni.us/ebN6T
Oil Based Poly – https://geni.us/JKoDbR1
Spar Varnish – https://geni.us/Bc1o
Hi, brilliant article!
I was wondering if I could get your opinion on exposed bathrooms beams?
We exposed the old roof beams in the bathrooms in our renovation project (16th century cottage).
Is it best to leave them alone or protect with something? If so what do you think will be best?
we want to keep them looking as natural and authentic as possible?
Thanks
Dorota
Hello Dorota,
I’m not sure which country you’re in, but if they’re the 16th century, the beams are highly likely to be oak or similar.
If they are now exposed, I’d look to protect them. If you wish natural and authentic, then oil is your only answer. You could use a satin polyurethane, but that’s hardly authentic.
I’d avoid linseed oil for a bathroom, as it doesn’t perform well around moisture, turning black. When your cottage was built, sailors used tung oil to preserve the wood in their ships. It penetrates and nourishes the wood before hardening and sealing it. I love tung oil, and I highly recommend it. Use at least three coats.
Here’s a link to a product I like, as it’s pure and therefore doesn’t change the color of the underlying wood: https://geni.us/Bc1o
All the best.
Thank you for this excellent webpage. I have an oak vanity worktop in my bathroom that I have sanded down ready to seal. I would like to stain it so thought I should go for the stain-sealer combo. However, I’ve noticed that the stain sealers you recommend (such as the readyseal) seem to be for exterior wood. Is that suitable for use in the home? Also, if I wanted to go belt and braces, could I use a varnish after it? Many thanks for your help
Hi Chloe. The stain-sealer sounds like a good way to proceed.
Don’t be concerned that they are external use products, for the most part, all that means is they have UV protection included. They will be fine for indoor use.
Yes, you could use a varnish over the stain-sealer, but frankly, it’s probably not worth it. The sealer has already sealed the timber and the varnish won’t add much utility.
That said, you may choose to use varnish if you want a shiny surface, however, be aware that the varnish may blister and peel in the future, as it’s a surface coating rather than absorbed into the wood like the stain-sealer.
Hi there – the timing on this article is perfect. I have two mosaics on furniture grade plywood that I would like to hang in bathrooms. One of the mosaics is grouted, one is not (tesserae style). Do you have any suggestions on how to prepare the wood to resist the fluctuations in temperature and moisture in a bathroom? Thanks for your help,
Shannon
Hi Shannon, there are two choices. You can use an epoxy or urethane sealing coat, or a hardening oil such as boiled linseed oil.
Bear in mind that the oil will take a long time to harden off (weeks) and will need reapplication every year or so, depending on the amount of moisture it’s exposed to.
The epoxy or urethane hardens off quickly and won’t need touching for years. Try a urethane such as this one: https://geni.us/v76c2, or an oil such as this: https://geni.us/NSA2jRQ.
Really helpful article- thanks so much!
Is there a particular brand of sealant you would recommend for protecting a window that inside a shower?
Any recommendations would be gratefully received!
Thanks!
Hi Emily, thanks, I’m glad you liked it.
I’m a fan of oil-based polyurethane in and around showers. Here’s one I recommend: https://geni.us/b3O94k.
You can use marine varnish, but frankly, its main advantage in my book is its UV resisting qualities, which is not a problem for inside use. If you wish to go marine varnish, here’s an option to try: https://geni.us/B1WvHH.
I hope it goes well!
This is such a great page- thanks! I have a similar scenario where I have an exposed wooden beam and wooden panelling above the shower so they get steam & some splashback. Would you also recommend Polyurethane for this?
I’m not sure where best to use varnish like yacht oil vs an outside wood oil vs hardwax oil! I should add this is for the UK/European product rather than US in case you know if specific products.
Thanks so much!
Jo
I should add – it’s a soft wood like pine.
Hi Jo, I’m pleased you found the page helpful.
Polyurethane is undoubtedly the quickest and easiest to apply; it drys quickly and lasts a long time. You can use an oil such as Tung Oil if you wish, but it can take 7 to 14 days to dry, while Linseed Oil can take longer.
Polyurethane creates skin over the timber and can hide a little of the grain and texture. The oil soaks into the timber, with quite a few coats required, but it reveals more of the grain and is usually a more matte finish.
It really is down to a mix of the look you require, the time you have, and how hard you want to work. Marine coatings are usually a higher quality product if you buy a good brand, with varnish used where looks are needed, and low wear is encountered. Oil goes on those bits that may take some knocks or abrasion, as it’s easier to ‘repair.’ Here are some links in the UK for each:
Tung oil: https://geni.us/5qEB, Polyurethane: https://geni.us/K5Bx1w, Marine varnish: https://geni.us/a56BXZj
The marine varnish brand is slightly more expensive than others, but it’s a tried and trusted product. I hope that helps!
Hi Mr. Stewart:
I am converting and old trundle style sewing machine to a powder room vanity.
I will be using a vessel sink.
The wood is dry but not cracked.
I think epoxy would be best, but how can I ensure the beauty of the gold oak is brought back?
I have used Boiled Linseed Oil for many years and am comfortable with it.
Can I use BLO to bring back the colour before applying epoxy?
Thanks.
Hello Ron, that sounds like an interesting project!
Yes, you can epoxy over BLO, but the trick is to let the linseed oil dry and harden off. I’m talking weeks here, not hours.
Some people I know leave it for up to a month, but that might be overdoing it. Good luck!
I am building a log home and I want to keep 2 of the log walls in the bathroom natural logs. What would be the best wood sealer to use to waterproof them? The logs are pine, and smooth.
Thank you
it’s brand new wood 🙂
Hi Josie.
Now I don’t claim to be an expert on log homes, as I’ve never built one. Yet, there is a rule when using whole logs to build with, that you don’t seal the surface of the wood.
That means no paint, or polyurethane. Anything that creates a non-permeable skinning surface tends to trap water in the logs and cause them to rot. The preferred use is a stain that penetrates the timber and protects it. You can choose oil-based or acrylic.
The oil-based allows a bit more of the natural grain of the logs to show through, whereas the acrylic stain covers more.
I’d look at the range of Minwax penetrating stains and select the look you prefer, available in this link.
Thank you
Hello William this was very interesting ,thanks.
I am buying a vanity made by engenering wood and I will be adding a sink on top for my bathroom. Do you recoment this type of wood for bathroom and if so what varnish/oil/seal should I use to protect it from water spil and humidity ?
Also what type of wood do you recomend the most for bathroom vanities
Many thanks in advance
Hello Laura, I’m glad you enjoyed the article!
Engineered wood is a generic term that covers a wide range of products. If it refers to laminated wood or plywood, it can be excellent for bathroom vanity use as it’s strong and resistant to warping. If it refers to medium density fiberboard (MDF), then I am less enthusiastic. MDF does not like water, and unless it is extremely well sealed, it expands dramatically and goes soft from water ingress.
That said, all timber in a bathroom must be well sealed. I’d use an oil-based polyurethane. I’ve had great results from this brand.
The type of wood I’d recommend in a bathroom would be a selection from maple, douglas fir, teak, or birch.
Hi William,
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.
Hello Andrew.
You can skip teak oil if you use teak sealers. Teak sealers include mildew-preventative chemicals. It creates a barrier that prevents the outer layer of wood from oxidizing, preventing your wood from turning grey.
Another advantage of teak sealers is that it doesn’t leave wood surface oily.
Teak oil is simply a temporary solution for enhancing the appearance of the wood. You can use it if you really want to, but you’ll discover that you’ll need to reapply for it every few months. This high-maintenance regimen may get tedious after a while.
I recommend applying a waterproof clear coat over stain finish as you will use this wood in the bathroom. you can use a product like this one by Minwax for the topcoat.
Thanks William, but what if I don’t want the finish to be glossy?
Hello Andrew.
If you don’t want the finish to be glossy, you can use something like this with Matte or flat finish.
Can you recommend a good Stain – sealant product. I will be using it on a bath panel
Hello Katherine.
You can use this product by Thompsons for your bath panel.
Hi William
We are up cycling an old pine sideboard which has already been painted into a vanity unit in a cloakroom (no shower or bath).
As the basin is only for washing hands how can we protect the painted work surface from water drips? The paint used on it is from B&Q home range furniture paint in a satin finish. Will two or three coats of this be enough or will we need some other sort of water sealant as well?
We did think we would need to buy a new waterproof worktop for the sideboard but someone said we didn’t really need to, any advice would be greatly appreciated. Thanks in advance
Hello Teresa,
You don’t need to buy a new waterproof worktop for the sideboard you can seal it. If the cloakroom has no shower and bath and the work surface will only come into contact will a few irregular water drip 2 to 3 coat of your stain paint is sufficient but if you want to go a step further you can apply a sealer on top of the paint you can use matt sealer to keep your satin look.
You can use something like this product to do the job.
Thank you very much for the advice.
My pleasure Teresa, feel free to ask me further questions or post comments on any future wood project you might have, will be happy to help.
I’ve been searching for months how to waterproof wood safely for my shower walls. In person everyone says “no” and the internet is all over the board. I’m chemically sensitive as well, so I need to use something that is low or no VOCs AFTER curing. I have no problem working with a respirator, good airflow and even outside if curing needs sunlight. I don’t mind waiting hours, days or even weeks for the method to fully cure. There will also be an excellent air vent in the shower. So my question is; Is there a way to truly waterproof wood well in enough for inside a steamy shower? And if so, what to use and how to do so with little to no VOCs after curing? Thank you for your insight!
Hello Reya,
You can use Epoxy resin to waterproof your shower walls. Epoxy is 100% VOCs free after it cures.
Epoxy is quite strong and can be used on various kinds of wood, and is completely waterproof. The main advantage of epoxy is it protects the wood while allowing it to retain its natural color; it forms a hard and durable layer that is stronger than paint.
Unlike paint, it can be reapplied without having to remove the older layer of epoxy.
You can use epoxy like this one.
You need to sand the surface to remove any dirt, debris, and loose particles. Then, apply the epoxy sealant.
Apply the epoxy in an even layer while it is still in a liquid state. Epoxy will dry pretty quickly once it comes into contact with a dry surface.
Excellent! Epoxy is exactly what I was thinking about using! Thank you so much!
My pleasure Reya, don’t hesitate to post me questions or comments you might have on future projects as well, happy to help
Super helpful article, thank you! I’ve got a new teak bathroom vanity. The manufacturer recommends a clear matte varnish. Is it ok to just do the outside of the unit and the inside of the drawers, or should I also do the inside of the cabinet that won’t really be subjected to any water contact?
Hello Sandi.
My recommendation would be to apply varnish inside cabinets too. Wood expands as humidity increases. As the humidity lessens, the wood starts to shrink again, your bathroom usually sees more fluctuations in humidity and temperature. The frequent change in humidity and temperature can cause wood to warp. Applying varnish inside also will reduce the difference in the humidity level in the wood which will reduce warping.
Hey William. I want to purchase a bamboo bench to put in my shower. It says its waterproofed already but I’ve read reviews on it where customers stated mold started growing. Is there a product I can use to waterproof it to prevent mold and mildew growing on it?
Hello Adam,
If the seller states it’s waterproof then it might have some type of finish done to it and the customer review might also be an isolated incident.
Urethane coating will work for your bench. You can use this one by Minwax.
William, I’m new at all this and very confused. I have an unfinished butcher block wood surround that absolutely needs to be waterproof. It also needs to be stained. Do I stain, use tung oil (and how much vinegar do I add?), General Finishes Topcoat after staining? Can you give me a “first do this, then this” answer? And product info would be really appreciated. Thank you.
Hello Mallow,
First, you need to stain the wood with the type of shade you want, Minwax has a verity of shades to choose from, something like this product by Minwax and let the stain cure.
After the stain is cured you can apply this finish by Waterlox to make your wood waterproof. Apply 4 coats in a well-ventilated area.
I have Thompsons wood sealant. Will that be sufficient???
Hello Ginger, what do you intend to do with the sealant?
Can you give me more information? I cannot say if Thompsons’ wood sealant will be sufficient without more information.
Hi there! I just saw this article! 🙂 Super great. Question – I have made a 10′ red oak vanity, I would like to add a little stain color to it, but need it waterproofed since the sinks/faucets will sit on it. I was trying to sort through all your comments, but got a little confused as to which would be best? Thanks in advance!!
Hello Stacy,
For Oak vanity, I would recommend using stain and sealer combo at it provides choice for the type of look you want and protection from water.
You can use this product by Ready Seal. This product works great with oak doesn’t require any primer before use.
The sealant is built-in and deeply penetrates the wood to provide exceptional water resistance. It has anti-mildew and anti-mold properties.
If you cannot find the type of stain and sealant you can use this product by Minwax.
You can apply the shade of stain you want and use this for protection.
Hi I am doing a van conversion and using tongue and groove pine ceiling in the van. I would like to run the ceiling across the whole van and was wondering how to seal it so it works for the roof of the shower as well.
Thanks
Sheila
Hello Sheila,
I would suggest you use stain with sealer for your van conversion. This method lets you choose the stain you want with good protection against moisture.
You can follow the instructions stated above in the article for the application process.
You can use something like this product by Roxil, this is an instant waterproofing clear treatment, it is easy to apply and will protect your ceiling for years to come you can use a stain of your choice before applying this.
Hi there,
I’m renovating my bathroom and want to make a natural wood panel look for the drop in tub skirt. What would you recommend we seal it with so it doesn’t accumulate drip stains over time? (Some one has told me to use yacht varnish)
Also would you be able to recommend a type of wood that would work best for
this?
Cheers,
Nicole
Hello Nicole, I would recommend Teak wood for the tub skirt.
Teak wood lasts several years. Even when used in the bathroom, teak has a long life span. That is due to the high resistance to water of the wood and is also rot-resistant.
The varnish used for yachts is great for this application as it will provide protection and a good finish to the wood. you can use something like this one by Rust-Oleum. Apply a minimum of 2 coats for the best results.
Hi William I am putting in a pine toung and groove ascent wall in my bathroom. Will not be in direct contact with water but moisture from the shower. Can I use tung oil to protect the wood?
Hello Pam, tung oil is water-resistant and will work great for your application and I would recommend something like this product by Hope.
Apply on wood that’s been sanded and cleaned. Let the oil soak into the surface, and reapply to any spots that look dry. Wipe off the residual oil, with clean dry rags to remove all excess.
I currently have 2 large floating vanity shelves. They are oak. They were custom made and came ready to be installed. I want to if possible, sand them down as they have yellowed and I want a much more “chalked” paler look. Can you advise me on what to use to achieve this???
Hello Emma, if you want to have a chalked look try chalked paint like this one by Rust-Oleum.
This will give you a matte finish with the current chalky look. It will not require any prep work. If you have a clean surface, sanding is not necessary. Try 2 coats for best results, apply wax after the paint is dry to touch.
We’re doing a loft conversion and an exposed overhead wooden beam will be directly within the showering area in the en-suite. What’s the best way to protect a structural beam from the water and steam? Many thanks
Hello Marnie,
The best way to protect a structural beam is to have the stem redirect from the shower to away from the beam. If redirecting the steam is not an option, you can use this product by Rust-Oleum.
It will protect your beam from water and steam. Try to apply 3 to 4 coats for the best protection.
William thank you for the excellent article. I’m turning an antique desk into a vanity with a vessel sink. The desk has a Birdeye maple veneer top that has some cracking which I don’t mind. I would like to protect the veneer against heavy water exposure. Would you suggest an epoxy?
Hello Daniela, I would suggest using the third method Waterproofing Wood with Stain and Sealer in the link:
https://woodimprove.com/how-to-waterproof-wood-for-bathroom/, you can use the Ready Seal product which is recommended in this article.
Just make sure you 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 afterward for a thorough finish.
This applies to both stains and stain-sealant combinations for complete protection as it will be exposed to water.
Alternatively, you can also use epoxy if you want to protect the veneer from heavy water exposure. It is a bit of hassle but if done correctly you can have wonders.
While applying epoxy, you will have a short amount of time to work with your epoxy paint before it begins to harden. You need to ensure that you choose a brand of good quality so that you can be certain of a flawless finish on your wooden surface like this one by Rust-Oleum.
You also have to remember that curing epoxy generates fumes that are toxic and any work with epoxy should be done in a well-ventilated room.
I have a vanity made out of coachwood, at the moment the cabinet maker used organoil , I have applied at least 4 coats and the slightest drop of water leaves a mark, could you recommend anything better to use please.
Hello Pam, I would suggest using a product like this one by Rust-Oleum.
Even though this finish is for exterior wood it will work great for your problem.
Changing brands and oil can change the finish of your cabinet so if you are happy with your current finish you can apply lacquer which will have a clear coat of protective layer.
What would you recommend for a child sensory/water table made from pine that would be exposed to water, things with food coloring, etc to prevent water damage and staining from the food coloring?
Hi Kristin.
Before applying any coating it is good the table has a good smoothness without roughness and small holes. The dyes can easily get into the small holes and stay there.
I think the wood sealant will do a good job, has excellent water protection, and has a long life.
This sealant is suitable for both outdoor and indoor use and has excellent water resistance.
I was planning to use sascho symphony to seal the logs in my bathroom. It is a water based product. Will this work and if so, how many coats should I apply?
Hi Randy,
I’m not familiar with this product, but most water-based products have good water resistance (you can check the manufacturer’s recommendations). Usually, 2-3 coats are enough or until you notice a thick layer of coating over the wood.
Hi William
Would spray coating a bathroom door with a NC paint be advisable
Hi Saurabh,
I don’t think nitrocellulose paint is the best choice. Once dry, it has good resistance and will provide protection but is more sensitive to moisture. In addition, when applied it is good to be in a dry environment without moisture (otherwise unwanted stains appear). A better choice would be polyurethane or acrylic.
I stained a bathroom vanity and then used Varathane on it. After doing so I realized that will not produce a waterproof surface. What can I do now to make this surface waterproof? Do I have to and off the finish before using a sealer or other product to make it waterproof.
Hi Joyce.
If your Varathane is water-based you can use a wood sealant like this one by Rain Guard has very good water protection and is suitable for both interior and exterior.
Before application, you can sand lightly with P220 for better adhesion. If it is oil-based you can use this varnish by Minwax which will adhere well to the oil base (the old coating must be well dried and sanded with P220 before applying the new coating), it is suitable for interior and has water protection.
Can you use both the tung oil and the stain sealant on bathroom countertops?
Hello Rod.
You can use tung oil or stain sealant. I’m not sure you can combine them and from my experience, I don’t think they will connect well with each other.
Hi William I am in the process of doing a Shiplap wall in my bathroom I want to make sure no moisture or mold get into it i also put along top of shower , not sure what to use for the gaps and ends of wood .. I want to stain it and waterproof it not sure what is best to use .. thanks
Hi Kim.
You can use this paint to color and protect your wall. The paint withstands harsh weather conditions so it will protect well in the bathroom.
It is a good idea to cover the boards on all sides before installing them to make sure that the wood is sealed.
For the edges of the wall, you can use sanitary silicone in a suitable color, it will protect from water and fill the gaps, it is also elastic and will withstand the expansion and contraction of the wood.
Be careful when working with silicone, it is easily smeared and can become a big mess if you try to wipe it!
Finally, after installing the wall, you can seal with wood sealant.
This one by Rain Guard has very good water resistance and is suitable for indoor use. It also protects against mold and mildew.
Hi William
We have fitted a countertop basin to an old pine dresser in our bathroom and have decided to tile the top as it’s already becoming water marked but how should we protect the surrounding wood which we’ve already waxed a couple of times
Thanks very much
Mandy
Hi Mandy, I can offer you two options:
The first is to continue to maintain the wooden parts with wax, you will have to apply once a year or when you see the first signs of wear.
This wax by Howard has good protection from water and protects the wood as a whole.
The wax is applied more often but also easier and the wax itself is easy to store.
Another option is to remove the wax with turpentine or another coating remover and apply a wood sealant like this one by Rainguard.
You will have more work to do to remove the wax and apply the sealant, but you will apply a new coating much less often once every 2-5 years.
Hi William
I am making a tongue and groove bath panel set. I would like a driftwood sort of colour, what would you recommend that is also waterproof as the wood, would be direct on the floor which does get wet.
Hello Mark.
You can use a water sealer on the raw panel to seal off the water. This product by Rain Guard will do a good job for you.
Then you can paint with water-based paint in the desired color. This paint by Rust-Oleum would work.
I am making a jumbo pegboard shelf for my bathroom what would you recommend to seal the insides of the holes for the pegs and the edges? What brands too? Thanks for the help.
Hi Arielle.
First, it is good that the edges are not too sharp, the sharper the edge the harder it is to keep the coating on it.
In case the pegs will move often, the better option is to treat them with boiled linseed oil like this one by Sunnyside.
The oil penetrates into the wood and thus protects it, there is no danger of the coating peeling off when moving the pegs.
You can use it directly or try some of the tips in the article.
Don’t forget to renew the coating at the first signs of wear.
Another option is to apply a sealant like this one by Rainguard.
This is suitable for both indoor and outdoor use. It will give you good protection for a long time. However, if the pegs are changed frequently, the coating is likely to peel off.
Choose according to your preferences and needs.
hello William,
Your article and comments are helpful and insightful. We have an oak worktop in the kitchen with the sink fitted into it, and the tap projects through the wood. I have finished with Osmo oil, which claims to be for worktops, but after only a short time the wood under the tap starts to go black and I have to sand down and start again. Is there anything more durable to resist the constant drip of water when wet hands operate the tap? Your advice would be much appreciated.
Hi Ken.
First, it is good to check if the seal between the tap and the wood is strong and if it is watertight. This can also cause the described problem. It is good that the tap hole is also treated with oil or sanitary silicone.
This oil by Osmo works well in general. Just remember oils should be refreshed more often, for example once a year.
You can apply thicker around the problem areas.
Hi William-we are making thick mahogany shelves for our large walk-in shower. They will be hung from the ceiling.They will be in high humidity but not direct water. What is the best finish to use? Thanks!
Hello Mary.
This seal by Rainguard is suitable for both outdoor and indoor use.
It will give you very good protection for a long time.
Do not forget to dilute according to the manufacturer’s instructions.
Apply several coats to obtain a thick coating. In the event that the coating is damaged by a scratch or impact, apply a new coating, it is important that the coating is complete.
Hello William,
Your post is very informative. I am purchasing a folding shower seat either made with walnut wood or finish(not sure). The seller says that it does not need to be sealed. How do i protect it from mold and mildew. after reading through your blog, I found boiled linseed oil at home depot. Will this do and keep the shower bench from rot, mold and mildew and water-proofed. What other steps I can take to ensure that the bench last s longer without any issues down the road. Advice is appreciated. Thanks!
Hello Nina.
First, it is good to know if the seat has any coverage and what it is.
The wood is probably heat-treated so that it does not absorb moisture, but you can still do the following for longer life:
If there is a coating such as a varnish or a sealant, you can apply sealant again to insulate the water.
If the wood is untreated then you can apply linseed oil.
To keep the bench for a long time, it is good to repeat the coating when necessary (discoloration, surface damage, etc.). Another important thing is that the wood is not constantly in water. I mean when no one is bathing, the bench is not immersed in water. For example, constantly retain water around the legs of the bench.
When there is good waterproofing and no abuse of water, the bench will live long.
Hi William,
I plan on turning my laundry into a bathroom, now my problem is the shower will be within the window and worried the wooden frame of the window will rot in time when it gets wet. Is there a way to protect the wood with another layer of waterproofing? The frame already has paint on it too.
Your feedback would be appreciated. Thank you.
Hi Patrick, you can apply a wood sealant to repel water like this one by Thompson’s.
It should match well with the window paint but it is good to test on a small area if it behaves well. Sand lightly with P220 before application.
Hi William,
I’ve had to purchase a “ready to paint” bath panel which I want to paint with colour matched paint to the vanity. The vanity is an eggshell finish so what would you recommend I use to seal the bath panel to ensure I have a similar finish
Hi Kay,
This Paint by Rust-Oleum has an eggshell finish and is designed specifically for bathrooms, laundry rooms, and basements. Prevents the formation of mold which is a major problem in the bathroom.
Hey William,
We are making a cabinet for a bathroom that is made of both solid wood and plywood. We wanted to stain it espresso. After reading your great article I wanted to find a stain/sealer combo but I am really struggling to find an interior one. I’ve mostly come across exterior ones. Is this too excessive for the project? What stain/sealer would you recommend? Thank you!
Hi Rachael, pleased to hear you liked the article 🙂
Yes, most sealants are for outdoor use, it is better to follow the manufacturer’s instructions and not to use for the interior (they have a heavier chemical composition which is not a problem in the open). Some sealants are safer and suitable for indoor and outdoor use. For your case, I would rather you use a stain for the interior.
This particular stain by General Finishes can do a good job for you, it has a good finish and is easy to apply.
Once you have chosen the right color, test on a board of the same wood to be sure of the end result, the thicker the layer, the darker the color.
After applying the color you can apply additional protection with a transparent coating like this one by General Finishes.
Apply 3 coats to get a nice thick layer. Drying time and long but the end result will be good.
Hi William,
I have inherited an late 19th C, early 20th century Swedish kitchen chair. I would like to use it in the corner of a large bathroom. We have mechanical fan above the glassed in shower cubicle and a window that can open next to the bathtub. It is safe to keep this chair in a bathroom? Is it suitable for oiling? Does beeswax count as oiling? TIA, Annette
Hi Annette,
Antique chair in a large bathroom! That sounds beautiful!
In your case, the chair will not be in direct contact with water and will not be exposed to high humidity so that the chair can stand in the bathroom.
Probably at the moment, the chair has some coating so oil is not a suitable option. The principle of action of the oil is to absorb into the wood and thus protect it (the old coating will prevent the absorption of oil).
The wax is more suitable because it stays on the surface.
Wax like this by Howard is suitable, protects from water, restores old furniture and gives them a better appearance.
The wax is applied periodically as it gradually thins and disappears. You will notice a difference in appearance.
Take good care of your Swedish kitchen chair and it will make you happy for many years to come!