How to Waterproof Wood for Outdoor, Bathroom, and Other Use

If the wood that you are using in your bathroom or outdoor area is not treated, learning how to waterproof wood is crucial. Because there is a high chance that it will either rot or start to warp over time. This is due to the fact that it is coming into contact with water, which isn’t a good thing for wooden materials. 

The last thing you want to do is to spend your hard-earned money on new furniture or other projects for it to be ruined due to water damage. This is why it is so important to waterproof wooden materials that are going to be used outdoors, in bathrooms, or around water. 

In this article, we are going to tell you exactly how you can do this yourself at home, so you can be sure that your wooden furniture is going to last for a long time.

It might not always be the easiest task, but it can be done by following the necessary steps. We are going to show you some different methods of waterproofing wood and how to best prepare your wood for outdoor or bathroom use.

Why Do I Need to Waterproof Wood?

You will need to how to waterproof wood that is going to be exposed to moisture.

You should even do this if the wood is water-resistant, as this wood is still going to absorb moisture if it has been continually exposed to it. A waterproof finish will create a tough surface that the water cannot penetrate.

Wood is a porous material that will absorb any moisture that manages to penetrate it, which can lead to damage.

The process will depend on the type of wood that you are using, but any wood that is being used outdoors or in areas with high moisture levels should be waterproofed. Otherwise, it will start to warp, crack, discolor, or rot over time.

The product that you are using to waterproof your wood can also offer other additional benefits, like UV resistance, protection against scratches and mold, and many other potential threats. Outdoor wood can absorb a lot of damage compared to sheltered wood indoors.

Ultimately, waterproofing wood will work to ensure that it lasts for a long time and keeps looking as good as new.

How to Waterproof Wood for Outdoor, Bathroom, and Other Use

Preparing the Surface

It is common for wooden pieces to have uneven or imperfect surfaces, and this can lead to waterproofing products not being able to stick properly to the surface. This will mean that it will be unable to do its job.

To ensure that the surface is properly prepared, you may need to get rid of these imperfections by sanding the surface using sandpaper. The surface will also need to be clean for you to get the best results.

How to Waterproof Wood for Outdoor, Bathroom, and Other Uses

We are going to show you a few different methods of waterproofing wood for outdoor, bathroom, and other uses, so you can be sure that your products are going to last for a long time.

Wood Sealer for Waterproofing

Wood sealers are one of the best ways to waterproof wood.

One of the best things about wood sealers is that you can add multiple layers and sand the surface to ensure that it is smooth and even. They also tend to dry much faster than other options.

However, wood sealers can be toxic, which means that you will need to use protective gear when working with them. You should also use it in a highly ventilated area.

Types of Wood Sealer

There are a few different types of wood sealer, including varnish, lacquer, and more. Varnish is probably going to be your best bet in this instance as it will not yellow over time.

It is even resistant to UV rays, and it is scratch and moisture resistant. Varnish is the best type to use in places that are exposed to high amounts of moisture.

Polyurethane is another great sealant to use as it offers a neat and smooth finish, and it comes in high gloss, low gloss, soft sheen, and a variety of other finishes. You can be sure that these products will make your wood pieces last for years to come.

Some people prefer to use lacquer as it is the most durable of these three options. It is scratch and moisture resistant and is not easy to damage. However, it has been known to yellow over time, even more so on lighter-colored wood.

All of these options have different purposes and optimal uses, and you should always check each’s details before buying. Some may be better for indoor use, while others are better for outdoor use, for instance.

How to Use Wood Sealant for Waterproofing

To prepare the sealer, make sure that you follow any instructions that come with it. You will then need to use a paintbrush to start applying the sealer to the wood surface.

Try to evenly spread the sealant across the surface of the wood and follow the wood grain for best results. Lightly rub your hand across both directions to feel the smooth direction which follows the grain. Once you have your first coat applied to the wood, you will need to leave it to dry for the product’s recommended dry time.

Once the first coat has dried, you will need to clean it to get rid of any imperfections. One of the best things to use for this is sandpaper and a damp cloth. Use the sandpaper to sand down any lumps and bumps, and use the cloth to get rid of any debris that is left behind.

Next, you can go ahead and apply a second coat if you feel that you need to. This is more likely to be necessary if you are using a softwood that is going to be continually exposed to moisture. For hardwood, a second coat might not be needed.

The last thing that you need to do is let it cure. This can take anywhere from 24 hours to a few days. Make sure that it has completely cured before you go ahead and use it.

The instructions will tell you how long the specific sealant will take to cure. Once it has cured, you can start using your finished product.

How to Use Hand Rubbed Oil for Waterproofing Wood

Another helpful option for how to waterproof wood is to use hand-rubbed oil.

You can either buy this pre-mixed or create your own mixture using linseed oil and Tung oil. This method will give the wood a dark rich color, and it is great for wood pieces that are going to be regularly exposed to moisture.

Once you have the product, you can apply it to the surface of the wood using a natural-bristle brush.

Make sure that the mixture is being evenly applied and that all of your brush strokes are moving in the same direction. Once the entire surface has been covered, allow the oil to sit for around an hour before you move on to the next step.

You can then use a clean cloth to rub the residual oil into the surface of the wood. Make sure that you are applying even pressure to do this, and keep going until all of the oil is gone. After this, you will need to allow the product the recommended amount of time to dry.

Finally, once the product has dried, you can opt to sand the piece with fine-grain sandpaper and apply additional coats if you need to.

How to Use a Stain-Seal Combo to Waterproof Wood

A stain-seal combo will work like the majority of sealants that you can get to waterproof wood.

One of the best things about them is that they will offer a wider range of pigment color options, and they will dry really quickly.

Stain-seal combos are perfect for waterproofing purposes, especially if you are looking for the most accurate color finish in a shorter amount of time.

These products can typically be found in a liquid form, and they can be applied to dry and clean wood. You will need to check the product packaging for the exact instructions in terms of how long it takes to dry and cure, and if there is any additional prep work that you need to do.

You should apply this product using a standard paintbrush, and you won’t need to mop up any additional product like with some other methods. This is due to the fact that the stain-seal combo will soak into the wood once it has been applied. This is also how it is able to dry so quickly.

Tips for Waterproofing Wood for Outdoor Use

When it comes to waterproofing wood for outdoor use, it can sometimes be helpful to choose the right wood for your region.

This is because it will be specifically designed to withstand the elements in your particular region. Something to bear in mind is that you may need to re-apply your chosen waterproofing method over time.

Also be aware that most waterproofing materials will kill plant life. You will need to cover plants near the work area with a drop cloth to keep harmful chemicals off your precious plants, flowers, and turf.

Another note on outdoor sealers and waterproofing. Water-based products can freeze if left outside during freezing night temperatures.

Tips for Waterproofing Wood for Bathroom Use

If you are waterproofing wood to be used in the bathroom, then you should make sure that you are only adding sealing products to wood that is completely dry all the way through.

To ensure that the wood is fully dry, you should leave it in a warm and dry place for at least 24 hours before you apply the sealant. 

You should also work in a room-temperature environment as areas that are too hot or too cold can affect the way in which the product you are using works.

This can lead to finished products that have dried and settled unevenly. Always avoid working in hot and enclosed environments and make sure to wear a mask due to the risk of the inhalation of sealant fumes.

Dean Luoma

As a long-time homeowner, Dean has been working on his own home projects for over 30 years. He is a licensed real estate agent in the state of Minnesota, helping clients with the buying and selling of their homes.

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