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How to Waterproof Wood for a Boat? – Only 5 Steps

Fact checked by William Hart

how to waterproof wood for a boat

Boat waterproofing is one key element to long-lasting vessels. In the old days, the Vikings used a Clinker construction, which involved overlapping wood planks and reinforcing the joints with rivets, to keep their boats watertight.

Sailors might also cover the wood with a natural application, such as pitch or tar. But regardless of how time-consuming and laborious the method was, it remained ineffective.

Nowadays, all you need to seal a wooden boat hull is high-quality epoxy resin, which provides outstanding waterproof and UV-resistant capacity. Keep reading to learn how to waterproof wood for a boat.

Table of Contents

Way to Waterproof Wood for a Boat

What to prepare

To make wood water resistant, you’ll need:

  • Marine grade epoxy and hardener
  • Marine waterproof paint (optional)
  • Hot air blower or propane torch
  • Sanding block and sandpaper; orbital sander
  • Foam roller and paint tray
  • Paintbrush
  • Acetone
  • Clean cloth
  • PPE (gloves, goggles, protective clothing, and a facemask)
  • Vacuum/cleaning brush
  • Boat soap and water

Remember to calculate the needed amount of wood sealer before purchasing. You neither want to waste your money on unnecessary materials nor come up short later.

The general coverage rate rule is six to eight square meters per kilo. Refer to the manufacturer’s instructions for the exact number.

Step 1. Clean the wood


The wood surface’s condition determines the smoothness and durability of the epoxy on top. So, prepare it scrupulously. If the wood is soiled, you need to wash it with boat soap and water. Doing so will ensure you won’t sand any contaminants further into the wood.

When the wood is dry, pour acetone on a clean cloth and wipe the boat to remove any remaining dirt, wax, or oil. Wait one to two minutes for the acetone to evaporate, and you can move to the next step.

Safety information: Wear gloves, protective clothing, goggles, and a facemask during the entire procedure to protect your skin, eyes, and lungs from debris and chemicals.

Step 2. Sand the surface


Grind the wood on both sides to prep it for the wood waterproofing epoxy. Proper sanding will provide texture for the epoxy to adhere to.

You should work the sanding block in circular motions and use sandpaper for crevices that the orbital machine can’t reach. When you finish sanding, wipe away or vacuum the remaining dust.

Note on the grit: The grit of the sandpaper tells us its abrasiveness. The lower this number, the more abrasive the paper is. For this step, we recommend starting with a low grit and switching to 80-grit sandpaper afterward.

Step 3. Apply the first coat of epoxy resin


Now, follow the instructions on the label to mix the epoxy resin and hardener. Be sure to choose the correct type of epoxy for wood; a fiberglass boat deck sealer won’t be as effective, especially if you are sealing wood for underwater.

Then, brush a light coat of the mixture on the wood. Start from the middle and work outwards to spread the wood boat sealer more easily. For large surfaces, transfer the mixture to a paint tray and use a foam roller to speed up the process.

If you come across any loose wood fibers while applying epoxy, stop painting until you’ve sanded and smoothened everything.

While the epoxy is drying, inspect it for any air bubbles, which usually show up when epoxy is used to waterproof the boat. The best way to remove them is to use a hot air blower or propane torch.

Hold the torch about ten inches away from the surface, turn it on, and slowly move through the troubled areas.

Step 4. Apply the second coat of epoxy resin

Waterproofing wooden boats usually requires two to four epoxy coats. So, repeat step 3 as many times as needed, but remember to grind the surface and clear it of dust before applying a new layer.

After that, allow the waterproof treatment for wood to cure completely. You may also give the boat a good wipe to make it spotless.

While curing, the epoxy might produce a wax coating. If you notice that, treat the wood with acetone.

Step 5. Paint the wood (optional)


Waterproof wood glue for boats is insufficient to protect the material from severe weathering at bays and seas. You should cover your vessel with UV-resistant marine paint to get long-lasting protection. Follow this procedure:

  • Stir to mix the paint and transfer it to a tray.
  • Dip a foam roller in the paint and lightly coat the wood. The first coat should be semi-transparent only.
  • Wait until the first coat dries and apply a second coat.

While the paint is drying, revisit your work and look for any areas that need touching up. Use a paintbrush to carefully add more paint to those areas.

Once you reach the desired coverage, let the paint dry naturally for at least 24 hours. Finally, wipe the entire surface with a clean cloth.

Though the steps we introduced will keep your wooden boat from water penetration and other damages, permanent waterproofing wood doesn’t exist, especially wood for outdoors. So, set a reminder to re-examine your boat and repeat the procedure every one to two years.

Why You Need to Seal Your Boat Wood

Unlike interior furniture, marine wood faces the harshest conditions: intense UV rays, water submerging, humid air, salt water, and extreme wind, all of which can weaken, abrade, and rotten the wood in merely a short period.

The most effective way to protect your investment is to coat it with epoxy resin and marine paint. The layers will prevent water penetration, discoloration, mold growth, and decay.

By spending money on high-quality epoxy for marine waterproofing wood now, you can significantly reduce the repair cost of the vessel in the long run.


With five straightforward steps, you can seal the wood of your exquisite vessel from marine weathering. Rest assured that the wood will stay in its ravishing condition for years to come, preserving the vessel’s value if you intend to trade it in the future.

Now that you know how to waterproof wood for a boat, quickly gather the materials and give your vessel the care and protection it deserves. We hope to see you around soon!

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