The best waterproofing for wood depends on your project. For exterior wood (like decks and fences), penetrating oil-based sealers are generally best. For boats or heavy-weather exposure, marine-grade sealers or epoxies provide the longest-lasting protection. For indoor furniture, water-based polyurethane works well.
Epoxy Resin
Epoxy is a two-part system: resin and hardener. When you combine them, a chemical reaction will change the liquid into a tough, totally waterproof finish. It completely seals the wood, filling every pore and creating a surface that water literally can't penetrate.
Wood sealers are primarily designed to protect wood from moisture and daily wear, whereas waterproofers create a near-impermeable barrier meant to withstand standing water and heavy outdoor exposure. Sealers focus on maintaining appearance, while waterproofers offer heavy-duty, long-term structural defense against rot and decay.
Waterproof sprays for wood protect outdoor decks, furniture, and fences from moisture damage, mold, and warping. The right product depends on whether you need a quick aerosol for small items or a larger spray-on formula for expansive surfaces.
Sealing outdoor wood requires proper preparation, the right sealant, and a maintenance plan to protect against sun (UV) and moisture damage.
To waterproof wood for outside use, start by sanding and cleaning the wood thoroughly. Next, apply a penetrating exterior sealer (such as a water-based proofer, exterior oil, or spar urethane) using a brush, roller, or sprayer. Let it dry completely according to the label, and apply a second coat for maximum protection.
Coal-tar creosote
Creosote was the first wood preservative to gain industrial importance more than 150 years ago and it is still widely used today for protection of industrial timber components where long service life is essential.
The most affordable way to waterproof wood is by starting with a natural wood oil and following with a coat or two of outdoor paint. Though more budget friendly in the short term, you will need to redo this method more frequently, as it is not as long lasting as, say, a pricier, high-quality sealant.
Best Waterproof Finish for Wood: Our Top 4 Winners
To waterproof wood, clean and sand the surface, then apply a protective barrier using penetrating oil, epoxy, or synthetic sealant. For best results, follow a multi-coat process, allowing the wood to dry thoroughly between layers to prevent moisture absorption, warping, and rotting.
Thompson's® WaterSeal® Clear Wood Sealer provides waterproofing protection for exterior wood surfaces. The clear sealer enhances and maintains the wood's natural color.
There's a risk of trapped moisture, which can induce mold growth and material failure. Some waterproofing methods limit flexibility post-application, potentially causing structural issues. Waterproofing can pose environmental concerns due to harmful chemicals and energy-intensive production.
No, you should not use WD-40 to seal wood. It is a petroleum-based penetrant and lubricant, not a wood sealer. Using it on wood will leave a greasy residue that never truly dries, attract dirt, seep into the wood grain, and permanently damage or ruin future paint or stain jobs.
Permanently waterproof
The advantages of a polyurethane coating cannot be denied. The most important advantage is the permanent impermeability it gives to the fabrics. Unlike a conventional impregnation or a DWR, a PU coating is resistant for a long time.
The best option for covering a wound for swimming is to use a waterproof plaster. These specially-designed bandages cover the wound area in full and provide a tight tape seal around the edges. This can help ensure that water does not penetrate the seal and the wound stays dry and covered.
Mod Podge does not make wood waterproof. It is a water-based acrylic sealer and glue, meaning it is only water-resistant. While it will protect decoupaged wood from minor splashes or a damp cloth, it will soften or peel if submerged or heavily exposed to the elements.
To permanently waterproof wood, encase it completely in a thick marine-grade epoxy. Since epoxy degrades under sunlight, always topcoat it with a UV-resistant sealer like spar urethane. For projects where flexibility and UV resistance are required, multiple coats of polyurethane or liquid rubber membranes are best.
Adiseal is the best external waterproof sealant due to its high UV resistance and permanent flexibility. It does not shrink or crack over time and features industry-leading mould resistance, ensuring a long-lasting, weatherproof barrier for masonry, windows, and outdoor structures even in extreme temperatures.
Spraying: speed and superior finish
It's fast and delivers that coveted smooth, even finish, free from brush marks. This makes it ideal for tackling intricate details on joinery, or when you're looking for a flawless, high-end look on larger surfaces like cabinet doors.
Spar Urethane. Spar urethane is a clear outdoor sealer that forms a barrier to protect wood from the elements. It protects wood from UV rays, rain, moisture, and temperature fluctuations. Spar urethane can be applied to natural wood or used over a wood stain in the color of your choice.
OLYMPIC WATERGUARD for Wood Waterproofing Clear Sealant offers convenience and value. A penetrating clear sealer that protects the wood while allowing the wood grain to show. Perfect for multiple wood surfaces.
Wood sealers are primarily designed to protect wood from moisture and daily wear, whereas waterproofers create a near-impermeable barrier meant to withstand standing water and heavy outdoor exposure. Sealers focus on maintaining appearance, while waterproofers offer heavy-duty, long-term structural defense against rot and decay.
The jar of petroleum jelly or Vaseline that you have in your medicine cabinet can work wonders to remove white water rings from furniture. The oily petroleum base penetrates the finish on the wood, displacing the moisture trapped inside, and the oils also nourish and condition dry wood.
Creosote was banned for consumer and general use because it is highly toxic and classified as a known human carcinogen. It contains a dangerous mixture of chemicals—including polycyclic aromatic hydrocarbons (PAHs)—that can cause severe skin burns, allergic reactions, and internal organ damage.
Restoring old wood comes down to assessing the condition of the piece. You can either revive an existing finish with a quick cleaning and polish, or completely strip and sand the wood for a fresh start. Choose the right method based on the wear and tear of your specific item.