How To Waterproof Wood For Bathroom?

Since wood is easily greeted with moisture, how to waterproof wood for bathroom is a frequently asked question when people come to construct bathrooms.

How can you maintain your lovely wooden floor without incurring the wrath of water and prevent harm being caused by water ever-present?

We hope our article will give you some helpful information to retain the beautiful wooden furniture without worrying about humidity.


What Kinds Of Wood Are Best For Bathroom?

1. Hardwood

Teak is considered as one of the few hardwoods with the right qualities for the wet environment because of their low shrinkage in changing conditions and high resistance to rot, fungi, and mildew.

Today, it is also the most commonly used decking material since it has natural slip-resistant features.

Teak is considered an ideal type to go for waterproofing your bathroom vanity top.

Teak does not have to be coated with much varnish, but it looks more beautiful when it is oiled but still retains the same qualities.

2. Softwood

Cedar, pine, and Douglas fir are also good choices for the bathroom.

Cedar, in particular, performs very well in rooms that have a lot of steam such as bathrooms.

It has unique natural fragrances and the shrinking factor is also very low in comparison to other types.

Softwood is highly rated for its resistance to warping, twisting, and checking.

Cedar is not only has a vintage look but also holds moisture well, making it perfect for modern homes.

Adding wood gives your bathroom a different vibe besides tiles and ceramics.

You can try mixing and matching different kinds of lumber, from furniture to towel racks for a more contemporary and eclectic look.

Guideline On How To Waterproof Wood For Bathroom

Basically, there are three safe methods of waterproofing your wood.

When choosing the solution that is right for you, bear in mind that some are tailored to dark or light grain timber, while certain waterproofing approaches are better suited to the interior or exterior pieces.

Tools and materials needed:

1. Coating with linseed or Tung oil for a protective hand-rubbed finish

Linseed oil, made from the seeds of the flax plant, and Tung oil, extracted from the Chinese Tung tree are two basic materials for most of all hand-rubbed oil finishes.

These oils beautify and preserve such dark grained woods as walnut and mahogany.

Whatever oil you want to use, follow these steps to help you waterproof wood in bathroom and retain water.

  • In order to provide a more powerful waterproofing compound, quicken the drying times, and prevent sticking, mix the oil with turpentine or apple cider vinegar. Make sure you mix thoroughly. You can still use the oil individually, this step is not a requirement.
  • Using sandpaper to prepare for flat, rough surfaces and boundaries. When you are done with the oiling, rough surfaces are visible and distasteful. That is the reason why this step is important.
  • Dip the brush into the oil and apply thoroughly without touching the surfaces and corners.
  • Allow a little bit of time for the surface and borders of the wood to absorb oil to identify untouched areas then reapply to those areas as necessary. The oil blends dry faster than the single ones. It can take a few hours, or even half a day if you use single oil.


Used rags are combustible even without being near flames because it creates heat as oil dries.

Take precautions by keeping a water bucket when working, also remember to wash with soap and water for the next applications.

Later, hang towels to dry separately. You can throw them off without risks when dry completely, but rags should not be reused.

2. Seal the wood with a coating of polyurethane, varnish, or lacquer

This method requires the use of sealants to waterproof wood for your bathroom.

The application steps are almost the same as oils. For the best result, seal your finish in a room temperature environment.

Moreover, do not shake or stir sealants before applying since it can cause surface bubbles, even after the sealant dries.

Sealants are not necessarily combined with any other natural or synthetic chemicals.

But you have to clean the wood dry, sandpaper it as the preparations before application. Let it dry after spraying or application with a brush is done.

Then apply again to ensure that the timber is protected from water.

These are the advantages and disadvantages of the most popular waterproof wood sealer for bathrooms:




– Contain acrylic, polyurethane, various other solvents, etc.

– Suitable to choose your favorite finish effect, from high gloss shine to gentle, soft sheen.

– Offer the greatest longevity.

–  Brush cleaning up requires mineral spirits or turpentine.

–  With water based polyurethane, cleaning up requires soap and water.


– Contain resin, solvent, drying oil

– Give a hard shell finish that resists yellowing and scratches.

– Marine varnish which has UV absorbers will be better for outdoor uses.

– Spar varnish helps to resist pesky cup rings, which is good for interior uses on end tables and coffee tables.

–  Be careful not to mix or stir strongly when applying since it will cause bubbles.

–  Cleaning up varnish requires lacquer thinner or mineral spirits.


– Contain dissolved tree resin or synthetic resin in alcohol.

– Bring a rich and warm finish to deep toned wood, which is also uniquely scratch resistant. Apply in multiple light coats for the best result.

– Available in a variety of sheen choices.

– Can be thinned with lacquer thinner.

–  Emit off strong fumes, which essentially requires ventilation, operating outside or opening of windows and using fans.


While these sealants also contain chemical solvents, they require ventilation during application although they are relatively easy to dry (sometimes as little as 15 minutes).

Check out this video on how to waterproof wood panels in bathroom:

3. Finish & waterproof wood simultaneously with a stain sealant combo

This kind of multitasking products not only add color but also provide water resistance in one single stage.

Stain sealant products contain color pigments and maybe oil, water, or alkyd-based binders.

The complete finish can be clear, opaque, or in between, depending on the pigment concentration.

Oil-based formula is best recommended for bathroom interior.

On the other side, alkyd-based is likely to peel if the wood is not perfectly clean and dry when applied, it is not suggested for waterproof wood in bathroom.

Note: You may have to reapply every year or two to keep the protective layer of timber.

How To Waterproof Wood For Bathrooms In Certain Areas?

1. Bathtubs

You have to make sure that the species of timber are selected from the beginning and regularly maintained. Japanese people have used cedar, hinoki, or teak to make soaking tubs.

Most experts advise multiple layers of sealant to provide continued protection.

To avoid causing leakage, keep the tub out of sunlight, apply sunflower oil to all surface areas, and maintain the moisture through the lib or cove if not in use.

2. Countertops & cabinet

Select the right kind of board for countertops that will create a warm, natural feel and reduce the spots on the surfaces.

When choosing tough timber as birch, beech, or maple to apply waterproof for bathroom vanity, although sandpaper can be used to refinish scratched board, it can be difficult to repair if the countertop is dented or weakened.

Butcher block (a laminated piece of hardwood) of walnut is a perfect choice.

The waterproof finish of bathroom countertop or cabinet should also be oiled once a month if it is not finished.

This protects the wood against most stains and damage to water, but frequent maintenance is necessary.

3. Walls or floors

As opposed to the cold feel of tile or ceramic, wood flooring has been preferred in bathrooms, due to its organic natural look and warmth to the touch.

In wet environments like bathrooms, make sure that you have a fan installed for proper ventilation to protect the walls from distortion and the risk of rising and mold and mildew.

You can also coat in some kind of sealant to waterproof wood for bathroom walls, such as linseed oil or polyurethane, to protect it further.

Make sure that you still cover all end grains even though they may not be exposed.

Frequently Asked Questions On How To Waterproof Wood For Bathroom

1. What Is The Difference Between Waterproof and Water Resistant Woods?

If a piece of wood is told to be waterproof, it means that it can resist water to a certain extent.

However, in the end, it will finally bend to the resilient forces of water.

On the other hand, a board that is water-resistant means that the wood is always protected from water forces.

2. Can I Use Hardwood In the Bathroom?

Yes, it is acceptable for installation in your bathroom.

It is recommended to put a rag by the sink because the water excessing can damage the wood.

However, it is not a good idea to furnished all your bathroom with hardwood.

Too much water or moisture also be soaked into the floor.

3. Does Pressure-Treated Timber Still Need Waterproof Protection Coating?

Yes. Even though pressurized lumber is pretreated with chemicals that prevent insect damage, it is not waterproofed.

Indeed, the application of this solvent allows the timber to dry out faster than natural ones and consume more water.

When your board absorbs water, it swells and will shrink when the board dries.

This wet-dry cycle causes crackling, warping, and spitting.

4. Are All Waterproof Products The Same?

No. They are different in the amount of water repellence a product provides.

For timber, it must be greater than 60% water repellence effective to satisfy minimum requirements.

5. How Long Does It Take To Apply Waterproof Varnish For Wood In Bathroom?

Time depends on how thick the layer is, even though all of the coatings are easy to use and dry in a few hours.

Basically, by the next day, you can use your boards without problems.


The answer to your question on how to waterproof wood for bathroom depends on the budget for your project. Do not let water be the reason why you cannot have rustic beauty in your bathroom. However, remember to take precautions such as gloves or eyes to cover since you are dealing with chemicals, not just liquids.

Further Reading:

Tags: 24 hours, wood from water

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