How to Waterproof Wood: 4 Methods


One of the biggest downsides of wood is that it isn’t waterproof.

Thankfully you can easily make wood far more water-resistant by using tung oil, varnish, paint or a sealant.

Here’s how..

1. Use Tung Oil

Tung oil is top-rated for waterproofing wood, along with walnut and linseed oil.

But tung is the safest out of the three, and it’s often included in commercial waterproofing products.

tung oil waterproof wood

Generally, tung oil is best used for small objects, like tables or small chairs but it can also be used to waterproof things like wood paneling in a bathroom.

If you have a large furniture piece, it’s better to use a sealant instead. It’ll be a more cost-efficient option.

Here are the steps you need for waterproofing wood with tung oil:

  1. Create a mixture of one part tung oil with half part of apple cider vinegar and one part of turpentine oil. You can use the oil alone, but the vinegar provides better perseverance.
  2. Grab fine-grit sandpaper and use it for sanding the wooden surface. That way, you smoothen all imperfections and prepare the wood for sealing.
  3. Wipe the wooden surface thoroughly using a dry cloth, making sure it’s totally dry
  4. Put on rubber gloves for protection, then grab a rag and fold it neatly to start spreading.
  5. Pour some of the mixtures on the rag, then spread it around on the wooden surface.
  6. Start moving in round motions, spreading the oil in the direction of the grain.
  7. Avoid touching the surface in this phase to prevent any imperfections, and spread the oil evenly to avoid clumps or an uneven coat.
  8. When there’s no more oil to spread, don’t rub the rag hard to release it. Pour some more on it and start laying again until there are no visible puddles.
  9. Wait for half an hour so that the oil settles on the surface, then wipe it gently to remove the remnants and the tough spots.
  10. Leave the wood for a whole day before using it, and make sure it’s dry first.
  11. Repeat the same process as many times as needed to completely seal the wood. If you’re in a humid area, it’s better to put 2–3 layers to make sure.

2. Use Varnish Or Polyurethane

Varnish, polyurethane, or sealants in general, are perfect for waterproofing wood.

They don’t just offer waterproofing properties, but they also protect the surface from scratches.

varnish for wood waterproofing

If you live in a family home or have kids around, varnishing the wood would be a wise choice to keep its surface shiny.

You can use varnish or polyurethane on any wooden piece of furniture.

Unlike tung oil, they work on large surfaces well. Here are the steps you need:

  1. Clean the wooden surface well before you start, then sand it using fine-grit sandpaper. You can use rough paper for the stubborn areas, then even it out with fine paper.
  2. Make sure to sand it properly to remove all remnants of any finish product that’s been there, or else the sealant won’t be absorbed. 
  3. After sanding, wipe the surface thoroughly, making sure it’s entirely clean and dry for the sealant.
  4. After choosing your sealant of choice, grab a paintbrush and dip it into the container.
  5. Use the paintbrush to apply an even coat of sealant. Before you do that, make sure to read the product’s instructions in case it needs to be used at a specific temperature or humidity level.
  6. Leave the wood to dry according to the amount of time recommended in the instructions. Most sealants need 10 hours maximum to dry.
  7. If your furniture is made of softwood, you may need to apply around three layers of the sealant for the best results. Repeat as many times as needed
  8. Leave the wood to cure for a week before using it.

3. Use Stain-Sealant

Stain sealants are pretty effective in protecting wood from water and other debris.

They close the pores on the wood, preventing any water from getting inside.

Plus, they keep the surface clean and protected from all liquids that may spill on it.

wood stain helps waterproof wood

Not only that, but most stain sealants include a pigment that protects the surface from UV rays.

The sun can cause the wooden furniture to dry and start showing cracks.

Stains prevent that, which makes them ideal for waterproofing outdoor furniture.

Here’s how to waterproof wood using a stain sealant:

  1. Clean the wooden surface well and sand it with a medium grit paper
  2. Even the surface out using a fine grit paper
  3. Wipe the surface with a dry cloth, then apply an even coat of the stain using a paintbrush
  4. Cover the wooden furniture, leaving it to dry for the recommended amount of time. It varies according to the brand you bought
  5. When the first coat is completely dry, apply the second one.
  6. Leave it until the surface is dry and not sticky to the touch. 
  7. Apply as many coats as you need, then leave the wood to cure for several days

4. Use Paint

If you don’t want to use a sealant or a stain, you can always use shellac paint.

Shellac is a type of resin that’s often used as a wood finish.

paint for wood waterproofing

It’s highly effective for sealing wood and waterproofing it, but it’s often the last choice because it’s more expensive than the other options.

On top of that, it’s not good for outdoor furniture because it scratches easily, and it can soften with time if it gets exposed to much water.

So, it’s better to use it on small items meant for indoor use. 

Here’s how to seal your wood with shellac paint:

  1. Create a mixture of shellac and alcohol, adding one alcohol gallon for every two pounds of the resin. Or, you can buy pre-made shellac if you don’t want to mix it.
  2. Test the paint on an old piece of wood to test its consistency so you know what you’re working with. You only need this step when using paint because it dries incredibly fast, and there’s no time to even it out
  3. Sand the wooden surface, wipe it, then apply a thin coat of shellac using a rag or a paintbrush. Make sure to apply the shellac to the cloth instead of applying it directly to the wood
  4. Wait for the paint to dry, then buff it out using a sandpaper
  5. Add more coats of paint until you’re satisfied with the shiny surface of the wood. Then, add one layer of wax to finish the wood

Final Thoughts

If you want to put your furniture outside for the summer, it’s time to start waterproofing it.

You have four options to choose from, and they’re all equally effective!

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