Waterproofing Wood

Wood that is untreated, especially when exposed to the elements, is vulnerable to rotting, warping, and cracking. Even interior wood baseboards in rooms such as the kitchen or bathroom where there tends to be a higher level of humidity are more susceptible.

Waterproofing wood

stux / Pixabay

To prevent any of these issues from happening to your deck, wooden patio furniture, or anything made of wood inside or outside your home, you need to be sure it is sealed.  There are plenty of products available from your local DIY store and most will contain some type of oil, either natural or synthetic.

Natural oils like tung or linseed oil are great at preventing rot, but they don’t protect the wood from UV rays. Another problem is that algae and fungus like these natural oils and feed on them, which makes your deck look less than stellar within a few weeks after applying it.

What Wood Finish Do You Prefer?

Depending on the project, here are the different types of sealants according to Home Depot:

  • Clear, multi-surface waterproofer: Used on both wood and masonry to stop water damage. They do not include mildewcides, pigments or UV blockers. If you apply this product to wood, it turns a weathered gray over time.
  • Clear waterproofer for wood: These products are specifically designed for wood and usually include mildewcides and help wood resist fading. Clear waterproofers enhance the natural wood grain’s appearance. Reapply every one to two years.
  • Tinted waterproofer for wood: Contain mildewcides and offer greater UV protection because they contain pigment. The color or tint enhances the wood color and allows the wood grain to show through. Reapply every two to three years.
  • Clear masonry sealer: Masonry sealers do not provide true waterproofing, but they do repel water and allow water vapor to move through the material. Apply these products to brick, concrete, block, stucco or other masonry material.
  • Pigmented masonry waterproofer: Pigmented waterproofers are similar to stains and change the color of the masonry material while also providing waterproofing. These products can be applied to any masonry surface.
  • Film-forming coatings: These masonry products resemble paint finishes – from sheen to satin to gloss. These products resist water pressure behind the film they create when applied. Use film-forming coatings to seal leaky basement walls. As masonry sealers, these products typically last the longest.

Applying the sealant requires some prep work, just as most stain or painting projects. Any imperfections will be intensified if you don’t take the time to sand them before application.

Use a coarse sandpaper to remove the blemishes and then finish with a fine grit sandpaper to smooth out the surface and allow it to absorb the waterproof finish. Some people prefer that weathered look, so then you can skip the fine sanding and move directly to the sealant.

But, if you want the natural grain to really stand out, the products that you use will require sanding in between each application. Since you can only put on one coat per day, you need to plan on a project like a table or chairs to take quite a while to finish.

This video demonstrates a very thorough re-finishing of a beautiful wooden patio table and benches:


If you don’t want to go to the lengths the creator of the video did, then you need to plan on doing yearly maintenance to the deck or furniture with some type of stain or sealant. If you aren’t sure what might work best on your project, this guide from Consumer Reports offers the best options for wood finishes depending upon the type of undertaking.

If you don’t want to spend that kind of time and effort on a job, then you can hire a contractor that will do the work for you. Depending on the size of the deck, your location, and amount of damage, the price ranges from $300 to $1,600 with the national average being close to $800 to have someone refinish your deck.