Waterproof wood is essential in building docks, patios and decks exposed to frequent rain or damp conditions. Wood is porous, so it absorbs water and, when it does, the wood expands and warps causing structural problems. While no wood is completely waterproof, a few species of wood resist water better than others, and some paints and sealers make wood waterproof.

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Wood can become waterproof with special treatments.

Water-resistant Woods

While all woods respond to water, some species last a little longer in wet and damp environments. Hardwoods in general have better water resiliency than softer woods like pine because the fibers are tightly packed together, resulting in less absorption, which does not mean all hardwoods are waterproof. Maple, oak and birch flooring expands and contracts due to moisture in the air. Even cedar, which is considered very water resistant, will warp in moist areas if not properly treated.

Waterproofing Stains and Sealers

A waterproof stain seals and colors wood to make it waterproof. Most waterproofing stains combine a sealing agent with the color dye, so both apply at once. Once the wood is dried, it will resist water for a prolonged period. As with other sealers and waterproofing products, stains are not permanent and often wear down over the course of just a few years. Stains are not the best waterproofing additive, but they are the most common and readily available. A sealer is made from polyurethane or a similar product and typically carries no pigment, unlike a waterproofing stain. Sealers apply right over the wood, creating a waterproof barrier.

Waterproofing Finishes

Another finishing product is a waterproofing finish, which provides luster and water protection to all types of woods but is most often used with hardwood furniture or floors. The finish contains a color agent, and it dries to a glossy shell for a shiny new finish. Finishes go on fairly easily with a paintbrush or spray painting gun, and they come in many different colors. The typical finish protects wood for up to 2 years and requires between 1 and 2 days to dry properly.

Stabilizers

The stabilizer is not a finish or a stain; instead stabilizers react with the alkali inside the wood to create a chemical reaction that makes the wood more waterproof. This product is perfect for docks or poolside decks, where the wood is in contact with natural elements or human activity, because it is organic, unlike a stain or sealer. To add more waterproofing, a stain or sealer is added over the stabilizer using a normal application process.