Preparing wood deck before sealing involves washing with what?

• A. Bleach and water
• B. Soap and water
• C. Acetone
• D. Oil

Answer: (A)

Cleaning a wood deck before sealing needs to address both dirt and any mildew or mold that can interfere with adhesion. Bleach and water is used because the chlorine bleach chemically kills mildew and mold on the surface, helping to remove gray, stained areas and brighten the wood so the sealer can bond properly. After applying a bleach-and-water wash, it's essential to rinse thoroughly and let the deck dry completely before sealing to ensure the cleaner residue and moisture don’t interfere with adhesion. Soap and water can remove dirt but doesn’t reliably kill mildew, acetone is a solvent used for finishes and can dry or damage wood, and oil would leave a slick residue that prevents proper sealing.