How to Waterproof Wood for Bathroom?

Wood is a natural material used for making furniture, floor, and wall panels. The brownish color gives a nice texture to your bathroom. However, wood is prone to swelling and rotting when exposed to moisture; especially in the bathroom.

If you are planning to use wood in your bathroom space. You will have to waterproof it to make sure it retains its original color and shape. You can make wood waterproof by adding a polish of Tung oil; sealing it with lacquer, or using a stain-sealant Combo.

Further, in the article, I will discuss in detail what chemicals you can use to waterproof wood and detailed methods to do so.

What chemicals you can use to Waterproof Wood?

Your bathroom is one of the humid and moist places; the wooden floor or panels used in there are prone to swell and rot if they aren’t made waterproof.

There are main three types of solutions/chemicals you can use to waterproof wood.


Two types of oil; linseed and Tung oil, have been used for years to waterproof wood in the bathroom. These oils are rubbed with hands to give a smooth, shiny, and waterproof texture.  Moreover, they are applied with some sealant, and mineral spirit, which reduces their stickiness and drying time.

Tung oil is from the Chinese Tung Tree. It is for all kinds of wood. Unlike other substances, Tung oil doesn’t form a layer on the wood. Instead, it gets absorbed and creates a strong water barrier from the inside. Though it is a good waterproofing agent, its curing time is high. It may take 7 to 10 for this coat to dry.

Linseed oil is extracted from the seeds of the flax plant. Just like Tung oil, Linseed oil also provides a water-resistant layer. However, its drying time is slightly higher than Tung oil.


Sealants made of varnish, lacquer, and polyurethane are great options for waterproofing. You can apply the sealant over the wood surface with a paintbrush or spray it.

  • Polyurethane contains different solvents as well as acrylic resins.  It is a great option for light-toned woods because now it doesn’t turn yellow as it once did.
  • Varnish is a scratch-resistant, non-yellowing finish. It is composed of drying oil, resin, and solvent.
  • Lacquer is another sealant used in wood waterproofing. It is composed of tree resin and synthetic resins. However, it is not vastly used since it can turn yellow over time and emits strong and toxic fumes.

Strain-Sealant Combos:

Stain-seal combinations greatly resemble regular sealants in appearance and behavior. Their main distinctions are a wider choice of color selections and a much shorter drying period. Therefore, stain-seal combinations are excellent for water resistance if you a very much into aesthetics and want an exact color match.

Method #1 WaterProof Wood Using Oils

Since you have known you have two choices to use for oils. Now, it’s time to learn how you can practically use them.

Step 1: Create a Solution for Waterproofing

Oils are commonly not used alone. We use them with a sealant such as polyurethane and a mineral spirit.

So, first, you need to form a solution of oil with sealant and spirit. The amount of mixture depends on how thick a coat you want on the wood. Stir the solution.

Step 2: Prepare the Wood

The solution cannot be applied directly to the wood. You need to prepare it for waterproofing.

Take sandpaper and smoothen its surface and all edges. Make sure all of the wood is clean and free from debris.

Step 3: Use Brush to paint the oil

Soak the paintbrush in an oil solution, and run it thoroughly over the wooden surface. Do this step repeatedly until no edge or corner is left untouched.

Step 4: Let it Dry and Add a Coat

 After you have completed the first coat on the surface, wait before doing the next coat. Let the surface absorb oil and do another coat after an hour. Repeat this step until you achieve the desired texture and surface finish.

Method #2 With Sealants

This method is pretty similar to the one mentioned for applying oil.  However, in this case, you don’t have to form a solution of sealant with another substance-you can apply it directly.

Most sealants are available at hardware stores in the form of cans or bottles, much similar to paint bottles. You can apply them to the wood with a paintbrush. However, the coats are done in series after the first coat has dried.

Sealants are also available in spray bottles. It is an easy method since you can spray the sealant directly onto the wood with a spray nozzle.

Method #3 Use the Stain-Sealant Combo

Nowadays, the most efficient and best way to waterproof is via stain-sealant combos. First, they are easy to apply and dry out quickly. Second, you get to see a wide range of color combinations.

You will find a stain-sealant combination in liquid form. So, you can apply it directly on a block of dry and clean wood with a regular paintbrush. However, don’t wipe off the extra liquid; it will get absorbed.  

Things to Remember When Waterproofing Wood

Since we have covered the three main methods of waterproofing a bathroom space; here are some main points to note:

  • When you buy a blended oil, it has three parts linseed/Tung oil, polyurethane, and spirit. To prepare the solution, mix the last two substances in the oil.
  • For thicker oil solution, add less spirit and vice versa.
  • Don’t ever use the wood shortly after the waterproofing. Give it time to dry; this will require a few days.
  • In order to increase the drying time of oil, you can add more polyurethane to the solution.
  • The alkyl-based stain-sealants are aesthetically pleasing and can be used in the rest of the house; however, they are not recommended for bath interiors


Finally, here’s a list of some frequently asked questions related to wood waterproofing.

How to protect bathroom doors from water?

You can protect your bathroom doors using either of the three ways. Apply Tung or linseed oil; use a sealant or stain-sealant combination.

Which kind of Wood is best for a bathroom?

For a bathroom vanity top that has to be waterproofed, Teak is a fantastic option. Teak does not need much varnishing, but it is way better if oiled since it keeps its robust qualities.

Final Words

Wood, being a natural substance, will deteriorate when exposed to water or moisture. So, it should be used with waterproof. Otherwise, it will rot in a very short span. To waterproof your bathroom, you can use oils, sealants, or their combinations.

Have any further questions, or want to share your thoughts on this? Let us know in the comments section.

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