How to Waterproof Painted Wood Furniture for Outdoors

Everyone desires to have an item of long-lasting wood furniture. Still, because the furniture is used outdoors, the weather will eventually have effects on them, making them weak, weathered, and eventually rot. Hence, it’s essential to know how to waterproof painted wood furniture for outdoors to increase durability.

There are various ways to waterproof wood furniture. Still, for painted wood surfaces, the paint has to be stripped off entirely before a primer is first applied, followed by a sealant or any other waterproofing agent such as wood oils, varnish, epoxy, and the likes. The paint has to be stripped for the waterproofing agents to get inside the wood and seal it to make it resistant to water. This article contains everything you need to know about sealing outdoor wood furniture.

How to waterproof painted wood furniture for outdoors

The following steps will guide you on waterproof your painted wood to make it durable enough to resist water and rot.

Step one: Clean the wood of its paint.

Get a liquid detergent and mix a quarter cup of liquid detergent with one gallon of water in a bucket. Scrub the surface of the painted wood with a cleaning brush placed in the soapy water.

Step two: apply a primer.

After stripping your wood of its paint, apply a primer coat evenly throughout the wood’s surface before applying sealant. The layer coat allows the sealer to last longer and making the wood waterproof.

Step three: Rinse and dry

Rinse thoroughly with clean water using a garden hose and allowing it to dry for three hours.

Step four: Apply a wood sealant.

Apply your polyurethane wood sealant or any other type of wood sealant evenly and leave it dry at least for a day.

How to waterproof painted wood furniture for outdoors using linseed oil and wood stain

Step one: Create a warm, hand-rubbed oil finish

For this first step, we will be using tung oil and linseed oil gotten from the tung tree and seeds of the flax plant, respectively. These two oils are mostly used to create a warm, hand-rubbed finish and have been used over the centuries for their great functions as they protect the dark-grained woods such as walnut and mahogany.

We can mix the two oils with a few other essential ingredients to make the perfect solution to waterproof your painted wood and the unpainted wood pieces. You can either buy pre-blended linseed and tung oil or buy them separately and mix them. A standard hand-rubbed oil mixture consists of either of the two oils, one part polyurethane, and one part mineral spirits. Here is the method on how to apply the mix:

  1. Mix and stir all the ingredients thoroughly.
  2. Use a natural bristle paintbrush to apply it to the wood pieces.
  3. Allow the oil to get absorbed into the surface. After that, you need to reapply another coat to the spots that look dry.
  4. Wipe off the residual oil using a dry towel or rags. This will remove all the excess oil from the surface.
  5. To Let the wood dry completely, this can take up to a few hours or preferably overnight, depending on the mixture’s amount of oil.
  6. After drying, use sandpaper and rub gently.
  7. Repeat the process till you get the desired finish.

Step two: Waterproof wood with sealant or stain

One of the easiest ways to seal your wood is by using wood stain or sealant. Using sealant makes your wood weather-resistant and durable, making it last longer. Sealants give a transparent finish, while wood stains give pigment that changes the look of the wood. Both sealant and wood stain makes the wood weather resistant, although it needs to be reapplied every few years to keep it waterproof.

Read Also: How to treat untreated wood for outdoor use.

The following steps will guide you on how to apply either your sealant or wood stain.

Prepare the wood

You need to prepare the wood by sanding the surface, and in this case, you need rough sandpaper to handle the surface, which will help you get rid of any other previous treatment. Make sure you use fine sandpaper to finish the sanding. Then clean the surface and remove the remaining sanding particles.

Select your sealant/ stain

Various brands produce sealants and stains, but you need to get sealants/ stains of high quality to get the best results. You need to choose your adhesive based on the furniture and the purpose you’re using it for. For example, you can purchase deck sealant and the likes. If you want your wood to be durable, resistant to moisture, water, and UV rays, you should go for marine wood sealant.

Likewise, if you’re using wood stain, make sure it’s meant for exterior use.

In case you’re dealing with large wood pieces or areas, it’s advisable to go for a product that can be used with a paint sprayer. This will speed up the application process and help save time.

Apply the first coat

Now that every other thing is set apply the first coat using a sprayer or brush. Ensure that you apply the solution evenly and cover all the portions well without leaving any space uncovered. Once done, let it dry for about 4-10 hours, depending on the manufacturer’s instruction.

Sand your pieces

You need to sand the wood pieces after the first coat dries up. This is important because it helps the next coat stick better. Ensure you use fine sandpaper. When you’re done, wipe off all the residue from the surface and get ready for the second coat.

Apply the second and third coat

Apply the second coat and leave to dry. Note that each coat will take longer to dry than the previous one. After the second coat is dry, use fine sandpaper for sanding the surface, use a spare towel or rag to clean the particles, and then apply the final coat and leave to dry.

Leave to cure

Leave the wood pieces to cure for at least 3-4 days before use.

Other ways to treat waterproof wood furniture for outdoor use

The best option to waterproof wood for outdoor use is through the sealing options, oils, and protective coats, which are preferable methods. The following are the best ways to treat untreated wood for outdoor use:

Outdoor wood sealers

Various wood sealers are extremely easy to apply. Water sealers are simply a combination of chemicals and oils that have several additions for advanced UV protection.

The primary purpose of wood sealers is to keep the inner wood dry and is best used for decks, fences, gazebos, and wooden exteriors and furniture. Timber treated with sealers lasts longer. It’s best applied using a brush. You can also apply it using garden sprayers. When dealing with large areas, it’s advisable to use a paint pad. It’s almost like a roller, but it’s flat, and it provides a better sealing finish.

Exterior paints

Paint has been used for a very long time. Simply choose an exterior paint that is waterproof and apply. Although it’s not the best option, it’s suitable for projects like outdoor tables, outdoor fences as it protects the wood from moisture.

Wood Oils

Wood oils have proven to be the natural method to protect the wood from natural weathering. However, when waterproofing wood, it is still advisable to go with more robust and more durable waterproof methods such as sealers. The most used outdoor oils are linseed, teak, and danish oil. When deciding what product to use, I’d recommend choosing based on the direct project. Choose specifically on specific outdoor furniture projects that provide weather resistance with the best natural look.

Clearcoats-spar urethane

It’s a suitable option for outdoor projects. They can be rubbed, brushed, and even sprayed on, making the application process easy, faster, and less stressful. They’re also practical for waterproofing painted wood furniture as it seals the wood surface, making it resistant to moisture.


Epoxy is a chemical compound that has excellent resistance to liquids. The moment you apply epoxy, you’re using a strong resistance to water. It is thick and will prevent water and surface damage to the wood. Epoxy is not UV resistant and will fade away over time if outside. Hence we will recommend a coat of spar or exterior wood oil on the wood pieces first.

You can also apply a small amount of UV protector, which will help save the color, then after it dries, you can layer epoxy over. Epoxy project is time-consuming compared to others as you will have to allow it to cure layer by layer.

Tools and materials needed.

  1. Mineral spirits
  2. Polyurethane
  3. Linseed and tung oil
  4. Natural bristle paintbrush
  5. Rags and towel
  6. Fine-grit sandpaper
  7. Liquid detergent
  8. Water
  9. Safety goggles.

Simple steps on how to waterproof wood for outdoor use

  1. Use linseed or tung oil to create a beautiful and protective hand-rubbed finish.
  2. Seal the wood with a coating of polyurethane varnish or lacquer
  3. Finish and waterproof wood simultaneously with a stain-sealant combination.
  4. While getting the approach suitable for you, note that some of those methods are better suited for either interior or exterior wood pieces.

Conclusion How to Waterproof Painted Wood Furniture for Outdoors

It is necessary to waterproof wood furniture to prevent wood rot. Using a primer on painted woods is vital as it improves the sealing and waterproofing agent’s efficiency. When using varnish, it’s more advisable to use marine spar varnish to be more efficient when waterproofing. You should follow the manufacturer’s instructions in detail to have desirable weatherproofed wood furniture.

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