How to Waterproof Wood- 3 Steps to Perfect Waterproofed Wood Floor

Do you know how to waterproof wood? Why is it important for woodworker to know how to waterproof? Kindly keep reading for more…

Wood is incredibly prone to water damage, and it needs waterproofing for added longevity.

However, taking care of every surface on your homestead and remembering every wood protection procedure is quite a task.

Therefore, check out this article for simplified steps on how to waterproof wood.

We have three surefire ways to waterproof lumber. Use tung or linseed oil or seal the wood with a polyurethane, lacquer, or varnish coating.

Also, you can finish and waterproof the structure with a stain-sealant combination.

It is okay to substitute linseed oil with tung oil, which is readily available.

In addition, the other two waterproofing methods will also deliver an excellent result.

Therefore, it is up to you to determine what works for your work.

Why Waterproof Wood?

Waterproofing helps protect the wood against multiple elements.

For instance, the water in wet lumber causes certain parts to expand, creating large cracks, warps, and splits.

This scenario leaves an ugly and unsafe surface, giving you enough reason to protect the wood.

Water and sun can stain, discolor, and break down the wood with constant exposure.

In addition, the wood may rot, leading to darkening, whereas regular and unprotected UV rays exposure can cause it to lighten.

Scratches and scuffs from heavy foot traffic may sound strange.

But damp wood is soft and scratches easily. So, the imperfection remains when the surface dries, often looking even worse.

Mold, mildew, and other organic growth is perhaps the worst problem for wood.

However, where moisture is not present, neither mold can be. Therefore, waterproofing wood keeps it dry and safe from these elements.

How to Waterproof Wood Furniture for Outdoors

Image of Wood Deck But What Size Nails For Deck Framing?Water and wood can mix well in certain instances; think floating decks, boats, and even beautiful driftwood.

But prolonged moisture contact has adverse effects unless the surface is waterproof.

In the absence of protection, the wood becomes stained and ugly, warps and changes shape, or rots and falls apart.

The lumber will eventually lose its structural integrity regardless of which problem occurs.

It is beneficial to protect the surface subject to foot traffic, outdoor elements, or heavy use.

Fortunately, waterproofing the surface is easy and protects the wood for longer.

Check out the procedures below for a professional outcome.

First, you need the correct project supplies; linseed oil, polyurethane, mineral spirits, natural bristle paintbrushes, fine-grit sandpaper, lacquer, wood varnish, stain, and sealant.

Then, choose the most suitable method, depending on the desired result.

Method 1: Create a Warm, Hand-Rubbed Oil Finish

Tung oil, extracted from the Chinese tung wood, and linseed oil from flax plant seeds are the basis for most hand-rubbed oil products.

They beautify and protect dark-grained lumber, like mahogany and walnut. In addition, the oils undergo improvements to eliminate stickiness and hasten drying time.

Here’s how to use the product:

  • Stir the formula thoroughly and apply it with a natural bristle paintbrush. However, this step mainly works on dark-grained wood as the oil yellows over time.

So, it is prudent to skip it for lighter wood, such as ash or pine.

  • Let the oil penetrate the wood, and reapply on any dry areas. Then, wipe off the excess with a clean rug.

Also, ensure the wood dries thoroughly before use. The waiting duration ranges from a few hours to overnight, depending on the oil degree in the mixture.

  • Sand the surface gently with fine-grit sandpaper. Keep checking the wood and repeat the steps with as many additional layers as needed to deliver a good finish.

In addition, feel free to experiment with the product.

  • Generally, you can create multiple custom blends.

But consider adding more polyurethane for a quicker drying time and a glossier surface or reducing the formula amount when working with more time.

Method 2: Use Sealants

Varnish, polyurethane, and lacquer are excellent sealants featuring superior waterproofing attributes.

You can either spray or brush them onto clean, sanded surfaces. Then, allow them to dry before lightly re-sanding and recoating the finish.

Apply the formula in a ‘room temperature environment for the best outcome.

But avoid briskly stirring or shaking the product before application lest you create air bubbles that will compromise the final finish.

Although the sealant dries pretty quickly, some in as little as 15 minutes, it contains chemical ingredients.

Therefore, working in a well-ventilated area is prudent to avoid health hazards.

Method 3: Work With Stain-Sealant Formulas

A quality stain product is perfect when time is of the essence or you are waterproofing a large surface, such as a wood deck.

The multitasking formula adds color while delivering superior water resistance in one step.

In addition, depending on the pigment concentration in the finish, the final result can be opaque, transparent, or in between.

Stain-sealants do not build up on the floor: instead, they penetrate the grain, and any excess evaporates.

However, alkyd-based formulas leave a light coating on the surface, making them a better alternative for interior wood, like rustic furniture or indoor exposed beams.

Also, outdoor, alkyd-based stain-sealers peel off if applied to damp or dirty wood.

Therefore, follow the recommended wood preparation and product applications procedures for a successful product.

Keep in mind that some waterproofing strategies are ideal for exterior or interior surfaces, while others work better on dark-or light-grained lumber.

So, consider the most suitable approach for your work.

Can You Paint Wood to Make It Waterproof?

Yes, you can paint wood to waterproof it. Moreover, a durable, water-resistant acrylic enamel is perfect for exterior lumber and protects it from weather exposure.

In addition, it does not need a top coat to protect it from abrasion and moisture.

Water can penetrate cracked paint and cause decay. Thus, it is advisable to use quality paint to seal the wood at various junctures.

In addition, the formula delivers a lovely, durable paint film.

How to Waterproof Wood for Bathroom

Wooden bathroom floors are a sight to behold.

And whether you opt for a local alternative like engineered lumber, or exotic hardwood, such as acacia, nothing beats the beauty of a nicely finished wood surface.

Also, the material is perfect for flooring in colder climates as it is warmer than tile.

However, wood is notoriously thirsty and absorbs water quite quickly. Thus, it is best to waterproof it to keep it safe from water damage.

In addition, soaked-up wooden surfaces deteriorate faster and attract mold, mildew, and other organic elements, exposing you and your family to health issues.

Luckily, we have two main strategies to waterproof bathroom floors; staining and sealing.

Stains penetrate deep into the lumber, thus protecting it while covering the surface entirely or highlighting the beautiful wood grain.

On the other hand, sealers are clear and reveal the wood’s natural appearance.

They also form a protective waterproof coat on the lumber surface, enhancing its beauty and longevity.

Another primary consideration when getting a waterproofing technique is whether the formula is water-based or oil-based.

The latter soaks into the wood more deeply and lasts longer but does not work well in damp conditions.

Meanwhile, water-based formulas are not as durable as their counterparts.

But they do not require a lot of wood preparation for perfect adherence and even work on damp lumber.

On top of that, please check whether the waterproofing product is tinted or clear.

Tinted formulas offer general wood protection to elements. And it is advisable to reapply every three years for maximum benefit.

On the other hand, clear formulas preserve the wood’s natural beauty and pattern.

In addition, their primary purpose is to prevent fading. But they need reapplication every two years for superior surface protection.

Consider four primary methods if you wonder where to start when waterproofing your bathroom floor.

Waterproof Bathroom Wood with Oil

Oil is one of the best waterproofing solutions for bathroom surfaces. It delivers a stunning and durable outcome.

In addition, you do not need capital upfront as readily available oils from the kitchen are enough.

There are several oil types to consider for the surface; linseed oil, teak oil, tung oil, hard wax oil, and walnut.

Generally, teak oil delivers the most exquisite surface, while hard-wax oil is the best option for durability.

Walnut oil triggers allergic reactions; thus, use it carefully.

In addition, hard-wax oil tends to leave a thick finish, requiring you to thin the formula before use.

Most woodworkers prefer tung and linseed oil. Tung oil comes from the Chinese tung tree and delivers a durable waterproof film over the wood.

In addition, it leaves behind a lovely wet-like surface.

Unfortunately, the finish takes longer to cure, typically seven to fourteen days, depending on the number of coats.

This drawback brings boiled linseed oil into the picture as it has a shorter drying time and still delivers a nice glossy and water-resistant surface.

In addition, the oil comes in multiple attractive finishes and colors. Therefore, you have a variety to work with for your project.

The formula will reveal all the colors on the wood surface.

Also, please note that any rough spots and imperfections on wood surfaces will appear after the oil application.

Therefore, you need to prepare the wood accordingly before beginning the work.

Consider the following:

  • Use a metal file or sandpaper to remove any blemishes on the surface.
  • Lightly sand the wood with 220 fine-grit sandpaper.
  • Sweep the surface or rub away scraps using a lint-free rag and leave it to dry.

Next, go ahead and waterproof the bathroom wood as highlighted below.

  • Fold a lint-free rag and keep other scrap cloths nearby. These accessories come in handy in removing rough edges and stopping potential snags when spreading the formula. Also, wear thick rubber gloves and get to work.
  • Pour a small oil amount on the rug and rub it along the wood grain, moving from the interior to the exterior. Also, avoid applying the oil directly to the surface, leaving standing puddles, or rubbing too hard.
  • Wait for about 30 minutes for the formula to penetrate the wood. Then, wipe away the excess and leave the surface for 24 hours to dry.
  • Sand the surface with 0000, very fine steel wood, after the first coat dries, and then apply two more oil layers. You can repeat the sanding between applications, but ensure that the second coat dries for 24 hours before having the third coat.
  • Leave the floor for at least three days to dry to the touch. You will know that the surface is fit for use if your finger smoothly slides across the surface.

Waterproof Bathroom Wood With a Sealant

Using a sealant is another practical strategy for waterproofing bathroom flooring.

In addition, the formula delivers outstanding water-resistance attributes without leaving imperfections on the surface.

The finished wood is usually smooth and glossy. And even better, you can recoat, re-sand, and paint the sealed surface.

The product also dries super-fast, allowing you to resume regular use after one day.

In addition, wood sealants are available in various forms, from varnish to polyurethane and lacquer.

However, waterproof varnish for lumber is the best for surfaces with frequent moisture exposure.

The finish also delivers a yellowing-free experience and is UV rays and scratch-resistant. Therefore, it is perfect for bathroom floors.

Polyurethane is an excellent option as it delivers an elegant, water-resistant, and durable finish.

In addition, it guarantees a successful project whether you want low-gloss, high-gloss, or soft sheen.

Finally, lacquer is the sturdiest as it features superior scratch and moisture resistance.

However, the only downside of the formula is that it yellows over time, making it unsuitable for light-colored woods.

The procedure for this strategy is as follows:

  • Remove any traces of past wood finishing. Next, smooth the wood with fine sandpaper and wipe the surface with a wet rag. It is okay to use rougher sandpaper for rougher spots and then finish the area with a smoother one.
  • Mix the sealers and stir for some minutes until it is ready for use. In addition, follow the manufacturer’s instructions for the best outcome.
  • Use a paintbrush to apply the formula and follow the wood grain. Also, move quickly to avoid exposure to toxic fumes or only work in a room-temperature and well-ventilated environment.
  • Let the first coat dry before applying subsequent ones. Luckily, the base coat only needs four to ten hours to dry. Thus, you can do the first finish in the morning and the second one in the evening.
  • Once the first one dries, apply the second layer and clean the surface with a fine-grit sandpaper. Next, add the second layer and the third if necessary. Also, please note that hardwoods generally need one or two coats, while softwoods work best with at least two to three sealer layers.
  • Give the wood several days to cure thoroughly. You will know that the floor is ready for use if water beads up and flows over the surface instead of penetrating it.

Waterproofing Bathroom Wood with Stain and Sealant

The third way to waterproof wooden bathroom flooring is by using stain and sealant.

We discussed the product in the previous section under various wood sealers. But a stain and sealant combination delivers a different outcome.

A stain sealant combination delivers a lovely, shiny surface and guarantees a high-grade darker appearance.

In addition, it dries pretty fast, allowing you to complete your project within no time.

However, choosing the correct formula for the job can be a big challenge. First, note that wood stains can be exterior or interior grade.

And you need the former for a bathroom floor as it experiences a lot of water and humidity.

Next, check the tone as wood stains are available in multiple shades, from very dark to very light. Generally, the lighter the hue, the higher the oil content.

But this category is better for interior applications or lumber with low humidity exposure. So, it’s prudent to choose darker options like a teak sealant for a bathroom floor.

Lastly, check whether you can get pre-mixed stain and sealant formulas. This way, you’ll save energy, time, and potential confusion when mixing.

Here’s the surface preparation and formula application procedure.

  • Scrape the surface with rough sandpaper, then finish it with a fine-grit one to remove noticeable imperfections. Then, wipe off the scraps with a dry rag or sweep the surface and wait for it to dry.
  • Prepare the stain sealant mixture if you got a pre-mixed formula. Calculate how much sealant you need for the floor and pour it into a large bowl or bucket. Add stain drops until the solution changes color. 
  • Use a paint roller or paintbrush to apply the first coat. Dip the accessory into the formula and gently apply it to the wooden floor, following the wood grain. Also, ensure that the application is as uniform as possible.
  • Allow the finish to dry and wipe away the excess. Depending on current weather conditions, the project needs four hours to a full day to dry. Then, rub the surface with fine-grit sandpaper and wipe with a rag once it dries.
  • Follow the same guidelines when applying the second coat. However, take even greater care not to spread the finish too much. Once done, let it dry for five hours to a full day before applying a third coat.
  • Give the surface a three-day drying duration after applying the final coat before resuming use. It is okay to test the finish after 73 hours, and you are good to go if it repels water droplets.

Waterproofing Bathroom Wood with Resin and Acetone 

The last waterproofing strategy involves using polyester resin and acetone.

Interestingly, this combination delivers the most durable outcome of all the above methods and can last five or seven years.

Once it dries, the waterproofing coat keeps out even little water or moisture traces.

Also, the finish dries faster and delivers a consistent surface, negating the need for sanding.

Please note that we have two types of polyester resin: finishing resin and laminating resin.

The former can work without a sealer, whereas the latter generally works over sealers and delivers a softer surface.

You can use both formulas for your product. Apply the laminating resin for the first few coats and finish with the finishing wax.

Then, after getting the desired finish, get the correct acetone.

The sole purpose of adding acetone is to thin the resin, making it easier to apply.

Therefore, you only need enough to make the job convenient. Then check out the steps below.

  • Please note that preparing lumber for resin application depends on the surface type.

For instance, it is advisable to use rough sandpaper before cleaning and fine sanding when working with reclaimed wood.

Conversely, you only have to clean the wood first, then use fine-grit sandpaper for weathered wood.

  • Pour some resin into a bucket or a bowl and add some acetone drops.

Stop adding the acetone once the mixture feels a little thicker than water. But you can continue adding if it feels too light.

  • Grab a paintbrush or roller, soak it in the mixture and apply gently, following the wood grain.

Take care lest the formula squishes on you.

  • You need to wait about 30 minutes between resin-acetone coats.

Also, it is best to apply up to five coats to get the best result.

  • Create a new mixture for each coat and avoid applying too much pressure when applying additional coats.

Otherwise, you may damage the previous layers.

  • Add some liquid wax after the final layer to enhance a shiny appearance.

Then, let the project cure for at least six hours. However, it is best to leave the surface overnight for a durable outcome.

How to Waterproof Wood Floors

The first step involves preparing the surface. Clear the room and clean the floor, repairing any damage.

Then, sand the wood and start with the edges to guarantee a smooth and consistent finish.

The next step is to select the most suitable waterproofing product and apply it to the surface.

Also, ensure that you read through the manufacturer’s instructions and adhere to them for the best outcome.

Usually, you need a minimum of three polyurethane or resin layers to get a durable protective finish.

In addition, allow each coat to dry thoroughly before adding the next one.

Watch out for wrinkles or bubbles and sand them before adding the next coat.

You can also use a natural fabric mop when you begin the process, then work with a brush. This way, you guarantee excellent coverage and an even finish.

Remember that it is best to work on a warm, dry day as the floor will dry quicker and uniformly, sparing you time, energy, and unnecessary fuss.

Also, move towards the door when applying the formula to avoid being trapped in the middle of the room. Otherwise, you’ll have to walk across the floor, ruining the work.

Nonetheless, regardless of how carefully you apply the formula, and no matter the claims by the product manufacturer, always wipe away spills as soon as they appear.

In addition, do your best to avoid flooding as it damages the floor despite any preventive measures.

Here’s How to Waterproof Wood Floor:


Unfortunately, waterproof lumber is not natural in the yard. Thus, it is prudent to maintain the wood and protect it from moisture, lest it swells or rots. In addition, check out more insights in the discussion above on:

How to Waterproof Wood

These days, waterproofing is not as difficult as it once was. You can use linseed or tung oil, seal the wood with a polyurethane finish, or apply special waterproofing formula, like varnish, depending on your preference.

Image of a woodworker wearing hearing protectors for woodworking

Tyron Otieno

Tyron is an avid woodworker and writer. He founded this website to help other woodworkers, whether hobbyists or professionals by sharing his knowledge and experiencie after a decade of woodworking.

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