How to Waterproof Wood for a Bathroom

Wood can effortlessly infuse any bathroom with natural elegance and a touch of warmth. However, it’s important to remember that wood is somewhat vulnerable to moisture, which can lead to problems such as warping, cracking, and the development of mold. Therefore, ensuring that the wood is adequately waterproofed is not only vital for maintaining its visual appeal but also for extending its lifespan. Now, let’s explore some of the most effective solutions for waterproofing wood in your bathroom.

Why is Waterproofing Wood in Bathrooms Necessary?

Being porous, wood naturally absorbs moisture, leading to expansion and potential deformation. As it dries, the wood may contract and crack, compromising its structural integrity and appearance. Over time, prolonged moisture exposure can also result in decay, particularly if fungi, bacteria, or insects come into play.

Decayed wood isn’t just unsightly — it may also pose health risks. Mold and mildew, often the results of such decay, can trigger allergies or respiratory issues. Waterproofing, therefore, is not a mere aesthetic choice but a necessary preventive measure. It can also be cost-effective in the long run, reducing the need for frequent repairs or replacements.

Methods to Waterproof Wood for Bathroom Use

Different woods and desired finishes demand different waterproofing methods. Here are some widely-used techniques:

1. Oil-Based Finishes

Historically, oil-based finishes have been a go-to for wood protection. They penetrate wood deeply, enhancing its natural color while providing a moisture barrier. Linseed oil, derived from flax seeds, and tung oil, extracted from the tung tree, are top choices in this category.


  • Start by prepping the wood: sand until smooth and wipe off any dust.
  • Mix the chosen oil with a solvent, like mineral spirits, to aid in drying. For added durability, consider adding polyurethane.
  • Using a natural-bristle brush or cloth, apply thin coats, ensuring complete coverage.
  • Allow the oil to penetrate for about 15 minutes, then remove any excess.
  • Apply multiple coats for best results, allowing ample drying time between each.
  • Buff the final coat to enhance shine.

2. Water-Based Finishes

These provide a clear barrier atop the wood, safeguarding its natural appearance. Common choices include polyurethane, varnish, lacquer, and acrylic.


  • Sand the wood smoothly and clean off any residue.
  • Apply the chosen finish with a synthetic-bristle brush or spray gun, covering the wood uniformly.
  • Allow each coat to dry thoroughly.
  • For added durability and a polished look, consider applying several coats, sanding lightly in between.
  • Buff the final dried coat for a refined finish.

3. Stain-Sealant Combinations

These dual-purpose products stain and seal the wood simultaneously. They’re an excellent choice for those wishing to modify their wood’s appearance while also waterproofing it.


  • Prepare the wood surface as described above.
  • Apply the product uniformly, ensuring thorough coverage.
  • Allow it to sit for 15 minutes, then wipe away excess.
  • Multiple coats may be necessary for the desired depth of color and protection.
  • Buff the dried final coat for an added shine.

Maintaining Waterproofed Wood in Bathroom

Waterproofing wood in your bathroom isn’t a once-and-done task. Regular care is necessary to maintain its appearance and durability without succumbing to moisture-related damage.

  • Clean Regularly: Use mild soaps or specialized wood cleaners. Avoid strong chemicals that could harm the finish.
  • Dry Promptly: After cleaning, dry the wood thoroughly to prevent mold or mildew.
  • Inspect Periodically: Check for signs of wear, like cracks or mold. Address issues promptly to maintain the wood’s integrity.
  • Reapply When Needed: Depending on wear and exposure, consider reapplying the waterproofing product every one to three years.


Waterproofing wood for use in bathrooms is crucial to prolong its lifespan, enhance its appearance, and prevent potential damage. To address common queries about this process, we’ve compiled a detailed FAQ for your reference.

Which woods are optimal for bathroom settings?

  • Teak: Renowned for its high oil content and tight grain, teak naturally repels water. This tropical hardwood is also resistant to decay, rot, insects, and fungi. While its golden-brown hue can gradually turn gray if untreated, its longevity in damp settings is unparalleled.
  • Cedar: This softwood boasts a natural preservative called thujaplicin, which offers protection against water damage and pests. Lightweight and user-friendly, cedar, with its reddish-brown tint, can fade over time without proper care.
  • Cypress: Cypress, a hardwood with substantial resin content, is another naturally water-resistant choice. It’s also resilient against decay, rot, and pests. Its yellowish-brown color may deepen over time.
  • Bamboo: While technically a grass, bamboo’s high silica content and dense structure render it similar to wood in durability. With eco-friendliness as a bonus, bamboo, which presents a light tan hue, is a green choice for bathrooms.

How can I ascertain if my wood is waterproofed?

To gauge your wood’s waterproofing, conduct a simple water drop test. Droplets that bead and roll off indicate effective waterproofing. Conversely, water that gets absorbed or leaves a mark signifies inadequate or damaged waterproofing.

How do I strip old or deteriorated waterproofing?

 Depending on the nature of your waterproofing, use either a chemical stripper or a mechanical sander. Remember to:

  • Select a method compatible with your previous waterproofing.
  • Adhere to safety guidelines, wearing gloves, goggles, and a mask.
  • Clean the wood surface post-removal, and ensure it’s dry before reapplying any waterproofing products.

Is it possible to paint over waterproofed wood?

Absolutely. However, proper surface preparation is crucial:

  • Lightly sand the wood for better paint adhesion.
  • Use a primer compatible with both your paint type and the waterproofing product.
  • Ensure thorough drying between primer and paint coats, applying 2-3 coats for optimal coverage.

How do I pick the best waterproofing product for my wood?

Selecting the right product involves considering:

  • Wood type: Different woods might require specific products to accentuate their natural characteristics.
  • Desired appearance: Choose between glossy and matte finishes.
  • Protection level: Some products offer enhanced protection against UV rays, mildew, or other potential threats.
  • Budget and availability: Whether you prioritize cost, convenience, or versatility can guide your product choice.

Final Thoughts

The significance of waterproofing wood for bathroom use cannot be understated. The method and products you opt for will hinge on various factors, from wood type to budget constraints.