How to Waterproof Wood for Bathroom?

Wood is quite often used in modern homes as a sink countertop. Some bathrooms also have wooden flooring as opposed to tiles. But the downside to wooden flooring is the fact that exposure to moisture makes it susceptible to accelerated wear and tear.

So, how can you prevent the deterioration of the wood in your bathroom? How can you waterproof the wood for your bathroom? You should continue reading to know the answers to your questions.

Waterproofing Wood in the Bathroom

Waterproofing all the wood in the bathroom is important so that it lasts longer. You should waterproof the wood if you want it to look its best for the foreseeable future.

Bathrooms are prone to moisture, humidity, and water exposure, which can damage wood over time, leading to warping, decay, and discoloration. 

Moisture can cause the wood to become moldy. The mold infestation will start to spread, which can be costly to remedy.

Waterproofing the wood will prevent moisture from piercing through the porous surface of the wood. Here are some tips to prevent moisture from damaging the wood.

1. Wear Protective Gear 

You should wear safety equipment before you go about waterproofing the wood surface. Here is the safety gear you should wear when preparing the surface of the wood.

  • Safety mask
  • Rubber gloves
  • Sturdy shoes
  • Long sleeve shirt

Wearing the aforementioned protective gear is essential to avoid getting yourself hurt when preparing the wood. You can safely prepare the wood surface wearing the above items.

Safety Information: Avoid applying the sealant to waterproof the wood in an enclosed environment. Make sure that there is proper ventilation before applying the sealant. This is important to avoid inhaling harmful fumes of the sealant.

If possible, consider taking the wood outside the house when coating the material.

2. Prepare the Surface

Before using a product to waterproof the wood, you have to first prepare the surface. This ensures that the waterproofing methods you choose will bond properly and provide long-lasting protection.

Follow these steps to get your wood ready for waterproofing:

  1. Clean the wood: First, make sure the wood surface is clean and free from dust, dirt, and grease. You can use a soft brush or a slightly damp cloth to wipe off any debris and allow the wood to dry completely.
  2. Inspect the wood for damage: Check for any cracks, holes, or other damages in the wood. These imperfections need to be addressed before moving on to the next step.
  3. Fill in any gaps: Use a wood filler to fill any cracks or holes that you found during the inspection. Apply it according to the manufacturer’s instructions, and let it dry before proceeding.
  4. Sanding: To ensure that the waterproofing material adheres properly, you’ll need to sand the wood surface. This can be done using sandpaper of varying grits. Start with medium-grit sandpaper (around 80-120 grit). This will remove the paint, seals, and any imperfections from the wood. Then move on to fine-grit sandpaper (180-220 grit). This step will create a smooth surface that allows for better adhesion of waterproofing agents.
  5. Remove sanding dust: After sanding, it’s essential to remove any dust or debris from the wood surface. You can use a tack cloth, a vacuum cleaner with a brush attachment, or a slightly damp cloth to remove the dust. Make sure the wood is completely dry before continuing.

Afterward, you should clean the area using a broom or vacuum cleaner. You should also clean the wood using a damp cloth or towel.

3. Apply a Sealant

You must apply a sealant to the wood to make it waterproof. There are different types of sealants you can apply on the surface.

Oil and Lemon Solution

Applying a mixture of oil and lemon can protect the wood from moisture in the bathroom.

This will not just preserve the wood but also add a pleasant smell to the wood. Moreover, a mixture of oil and lemon will remove any stains from the wood.

Just add drops of lemon in tung or linseed oil. Fill the spray bottle with a mixture of oil and lemon.

Make sure to spray the solution directly onto the wood. Wipe it off to remove any stains. The oil mixture will penetrate the pores of the wood making it waterproof and give a nice glossy finish.

Tung oil is preferable over linseed due to a longer curing time. But if tung oil is not available you can use boiled linseed oil to waterproof the wood. The preparation process for both oils is the same.

A gallon of tung or linseed oil is enough for about 400 square feet of wood. You will have to apply at least four coats of the solution. The oil will get absorbed into the wood creating a waterproof barrier.

One downside of using oil and lemon sealant is that the drying time is quite long. You may have to wait between one to two weeks for the solution to dry. The exact time will vary depending on the size of the wood you want to waterproof.

You can also use a thinning agent to reduce the drying time. But thinning is not recommended for weathered or unfinished wood as the solution won’t properly penetrate the wood.

Polyester Resin

You can also apply the polyester resin to make the surface waterproof. A polyester resin has a much shorter drying time as compared to oil. Moreover, it can also be used to restore damaged wood. You can use a finishing resin or a laminating polyester resin.

  • If you want to preserve the warm look of the wood, you should use a finishing resin that contains a wax that hardens on the surface.
  • A laminating resin is recommended if you want to pain the wood while preserving the surface.

The application process for the polyester resin is the same as the oil and lemon solution. You should apply the solution after preparing the surface. You should mix the polyester resin with acetone to create a smooth finish.

Just add the resin to a bucket and gradually add the acetone.

Continue to add the acetone until the solution becomes slightly thicker than water. To avoid diluting the mixture, you should make sure to not put too much acetone.

Use a soft-bristled paintbrush if you are coating a small surface of the wood like the wood surrounding the vanity mirror. For applying on the wood countertop or floor, you can use a paint roller.

You will have to create a new mixture for every coat. You must clean the roller or the paintbrush after each coat. For the best possible finish, it is recommended to wait about 30 minutes before the application of the next coat.

You can also add a few drops of wax to the final coat to give a shiny look to the wood.

Polyurethane Sealant

Polyurethane sealant is another great option to waterproof the wood. The sealant is a mixture of polyurethane and acrylic mixture with different solvents.

The sealant can give an attractively glossy finish to the wood. Moreover, the sealant can give a gentle sheen that will improve the look of the material.


A varnish will provide a nice finish to the wood, while also preserving the material. It is a mixture of solvent, resin, and drying oil, which will help protect the wood.

The mixture will protect the wood from turning yellow due to exposure to moisture.

Spar varnish is recommended for wood in the bathroom as it creates an excellent water barrier. You can apply the varnish on the wooden vanities and cabinets.

Applying the varnish is easy and the drying time is just 15 minutes.

Commercial Sealants 

You can also use a commercial sealant for waterproofing wood in the bathroom. Most commercial sealants available in hardware stores consist of varnish, polyurethane, and lacquer.

Commercial sealants are effective in waterproofing and also giving a rich color to the wooden surface. Moreover, they dry more easily and require less frequent reapplications.

You can use the sealant waterproofing wood both inside and outside the house.

Most sealants are available in the bottle or can. You can purchase commercial sealants with varying strengths and durability.

Similar to other sealants, you have to apply the commercial sealants to a dry and clean wood surface. Use a paintbrush or roller to apply the sealant. Leave the sealant to dry for two to three hours before the application of another coat.

It is recommended to apply at least five coats divided over a period of two days for the best results.

You can apply as many coats as possible until the desired results are achieved. The more coats you apply, the more will be the level of protection.

Some commercial sealants are also available as a spray-on can. The mixture is easy to apply using a built-in spray bottle. You should check the label for the correct method for applying the sealant.


Lacquer is a mixture of alcohol and dissolved resin. You can buy it in a wide variety of finishes at your local hardware store. You should use a thinning agent to dry the sealant faster.

An important thing to note is that the sealant emits strong, toxic fumes. So, you should only apply the sealant by taking the wood outside in the open air. Once the sealant has dried completely, you should bring the wood inside.

Another thing to note required the sealant is that the wood can develop a yellow tinge. It is recommended to use the sealant on deep-toned wood. Using the sealant on light-toned wood will not give the best results.

4. Waterproof Paints

Lastly, you can consider using waterproof paints specially formulated for wood.

These paints create a barrier to protect your wooden surfaces from moisture, reducing the risk of swelling, warping, and other damage caused by water.

Here are the steps to using waterproof paints for your bathroom furniture:

  • Clean your wooden surface thoroughly.
  • Apply a coat of primer to prepare the wood for painting (optional but recommended).
  • Paint the wood using a suitable waterproof paint, following the manufacturer’s instructions.
  • Let the paint dry and cure for the time specified on the label (usually 24-48 hours).

Caring for Waterproofed Wood

Congratulations on waterproofing your bathroom wood! By taking this step, you’ve increased the durability of your wood surfaces, potentially protecting them from water damage for years to come.

However, it’s essential to maintain and care for the wood consistently. Here are some recommendations on how to preserve your waterproofed bathroom wood:

First, make it a habit to wipe up any excess water or moisture whenever you see it on the wood surfaces.

Even though the wood is now waterproof, standing water can still cause long-term damage in the form of swell or rot. Use a dry, soft cloth to gently blot the moisture.

Next, ensure proper ventilation in your bathroom. Adequate airflow is crucial for preventing excessive humidity levels, which can lead to moisture issues and cause even waterproofed wood to warp or attract mold over time.

You can achieve good ventilation simply by opening a window while using your bathroom or installing an exhaust fan.

As a preventative measure, regular cleaning is necessary. Use a mixture of water and a small amount of mild soap or detergent to clean the wood surfaces gently.

Be cautious not to soak the wood with the cleaning solution, as this might weaken the waterproof coating and expose the wood to water damage.

  • Tip: Some people also use apple cider vinegar as a natural cleaning solution. Mix one part apple cider vinegar with ten parts water for a gentle and effective cleaner. Always test the solution on a small, inconspicuous area first to ensure it doesn’t damage your wood surface.

Lastly, periodically inspect your waterproofed wood surfaces for any signs of wear or damage.

If you notice the waterproof coating beginning to deteriorate, it’s time to reapply the protective layer. This step is essential to ensure your wood stays protected and maintains its appearance over time.

By following these simple care tips, you can effectively maintain and protect your waterproofed bathroom wood, ensuring a beautiful and damage-free surface for years to come.

Understanding Wood Types

When waterproofing wood for your bathroom, it is essential to understand the different types of wood and how they respond to moisture. The main categories of wood are hardwoods and softwoods.

Hardwoods are generally denser and more resistant to moisture. Their durability makes them a good option for bathroom projects. Examples of hardwoods include:

  • Oak
  • Maple
  • Teak

Softwoods are more porous, which means they absorb water more readily. They are less suitable for bathroom use unless properly treated and sealed. Examples of softwoods are:

  • Cedar
  • Pine
  • Douglas fir

In addition to solid wood, plywood is a commonly used wood product for bathroom construction. Plywood consists of multiple layers of wood veneers pressed together, and it is generally more stable and water-resistant than solid wood.

When choosing the right wood type for your bathroom project, consider the following factors:

  • Durability: Hardwoods are more durable, but you can still use softwoods if properly treated and sealed.
  • Maintenance: Hardwoods usually require less maintenance than softwoods, but sealing and regular upkeep are essential for both types to ensure their longevity.
  • Aesthetics: Each wood type has its unique color, grain pattern, and texture. Make sure to select a wood type that complements your bathroom’s design.

To ensure a successful waterproofing process, take into account the type of wood you’re working with. Hardwoods usually require fewer coats of sealant, whereas softwoods might need extra layers for better protection.

Ultimately, the key is proper preparation, application of the right waterproofing materials, and regular maintenance to keep the wood in your bathroom in great condition.

Alternative Flooring Options

When looking for bathroom flooring options, it’s important to consider alternatives to wood that can better withstand exposure to water.

Here are some popular choices, which are not only water-resistant but also easy to maintain and stylish.

Vinyl: Vinyl flooring is an excellent choice for a bathroom. It’s affordable, available in various designs, and provides a warm and comfortable feel underfoot.

The SPC core of luxury vinyl is completely waterproof, making it a reliable option to prevent water damage in your bathroom. Luxury vinyl often includes a soft, pre-attached foam underlay for added comfort.

Laminate: Laminate flooring is another option to consider. It imitates the look of wood but offers better resistance to water and moisture.

Remember, though, that laminate is not as waterproof as vinyl and may require an additional moisture barrier to protect it in a bathroom setting.

Ceramic Tile: Ceramic tiles are classic and versatile in bathroom design. They come in a wide range of colors, patterns, and sizes, allowing you to create a unique look.

Ceramic tiles are water-resistant, durable, and low-maintenance, making them a great option for your bathroom.

Keep in mind that tiles may feel cold underfoot, so consider using them in combination with rugs or heated floors for added comfort.

Plastic: In high-moisture areas like your bathroom, plastic flooring options can be practical and budget-friendly.

Many types of plastic flooring, such as vinyl planks and tiles, can simulate the appearance of wood or other luxurious materials.

Plastic flooring is water-resistant and easy to clean, which allows it to maintain its appearance despite exposure to moisture.

These options, such as vinyl, laminate, ceramic tile, and plastic, offer distinct advantages in terms of water resistance, durability, and aesthetics. So, before you decide on wood for your bathroom, consider these alternatives.

Frequently Asked Questions

What is the best waterproof paint for bathroom wood?

The best waterproof paint for bathroom wood is a latex-based, water-resistant paint specifically designed for use in wet and humid environments.

These paints are typically easy to clean, resist mold and mildew, and provide a durable finish that can withstand the constant moisture in a bathroom setting.

How do you seal and protect wood in a shower?

To seal and protect wood in a shower, follow these steps:

  1. Clean the wood surface thoroughly and allow it to dry completely.
  2. Sand the surface using 150 or 220 grit sandpaper, depending on its roughness.
  3. Apply a water-resistant primer to the wood, following the manufacturer’s instructions.
  4. Once the primer is dry, apply at least two coats of a water-resistant paint or sealer made specifically for use in wet areas, allowing each coat to dry fully before adding the next.

What is a recommended clear waterproof sealant for bathroom wood?

A recommended clear waterproof sealant for bathroom wood is a polyurethane sealer, which provides a durable, water-resistant finish.

You can choose between oil-based and water-based polyurethane sealers, both of which offer excellent protection from moisture, stains, and abrasion.

How to properly waterproof wooden bathroom doors and floors?

To properly waterproof wooden bathroom doors and floors, follow these steps:

  1. Clean the wood surface and ensure it’s completely dry before starting.
  2. For doors, remove hardware and hinges to ease application. For floors, remove any baseboards or trim.
  3. Apply a water-resistant primer to the wood.
  4. Once the primer is dry, apply a water-resistant sealer or paint that is specifically designed for wet areas. Choose a product that offers slip resistance for floors.
  5. Allow the sealer or paint to dry according to the manufacturer’s instructions, then reattach any hardware, baseboards, or trim.

What is the most effective wood sealer for indoor use?

The most effective wood sealer for indoor use is a polyurethane sealer, which not only protects wood from moisture but also offers excellent durability and scratch resistance.

It comes in various finishes, such as gloss, semi-gloss, and matte, so you can choose the one that suits your design preferences and wood type best.

How to maintain wooden bathroom furniture for long-lasting protection?

To maintain your wooden bathroom furniture for long-lasting protection, follow these guidelines:

  1. Apply a water-resistant sealer or paint to all the wooden surfaces, repeating the process every few years or as needed.
  2. Clean the furniture regularly using a soft, damp cloth and mild soap, avoiding harsh or abrasive cleaners.
  3. Immediately wipe up any spills or splashes on the wood to prevent water damage.
  4. In areas of high moisture, like the bathroom, consider using a dehumidifier or exhaust fan to help control humidity levels.

Final Recommendations

Commercial sealants offer the best results for waterproofing the wood in the bathroom. However, using an oil-based sealant often provides a better finish. In addition, the oil-based sealant is more durable as compared to a water-based commercial sealant.

Each sealant has a different curing time. Resins take just one day to cure. Commercial sealers including varnish take about a week to cure. Oils take the longest to cure often requiring a wait of up to two weeks.

An important point to remember regarding sealants is that they don’t last forever. You will have to reapply the sealant at least once every two years to preserve the wood. Moreover, you should apply four to five coats for the best protection of the wood.

Lastly, you should avoid a hot or cold environment when applying the sealant.

This is important otherwise the sealant won’t dry and settle properly. The sealant should be applied at room temperature. For the best results, remove the wood from the bathroom and apply the sealant outside the house.

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