Before you begin

  • This product contains bleach. Handle with care.
  • A trial patch is recommended before starting. If the surface has been previously treated with a waterproofer, splash the surface with a glass of water. If it beads, dampen the wood slightly before using Thompson's® WaterSeal® Deck Wash.
  • Remove all deck furniture and decorative items. Do not allow product to come in contact with painted or finished surfaces that you do not intend to restore.
  • Saturate the ground around plants and shrubs with fresh water prior to application. Then cover all plants and shrubs to protect them from overspray. Uncover promptly after use.
  • Wear protective gloves and old clothing. Do not allow product to come into contact with clothing, carpet or fabric, as discoloration can occur. When spraying, use eye protection.
  • The longer Thompson's® WaterSeal® Deck Wash is allowed to work, the lighter the wood will become. Do not allow Thompson's® WaterSeal® Deck Wash to remain on the surface for more than 30 minutes, as an uneven appearance may result.
  • Thompson's® WaterSeal® Deck Wash may slightly darken Redwood or Cedar. To brighten wood after cleaning with this product, use Thompson's® WaterSeal® Deck Cleaner & Brightener.
  • Plan the application: for horizontal surfaces, work backwards so that you do not walk on the surface being treated. For vertical surfaces, work from the bottom up.
  • Exercise caution when working on wet surfaces.
  • Thompson’s® WaterSeal® Deck Wash can also be used on exterior painted surfaces to remove stains from mildew if diluted 50/50 with water.


  • Add contents of container to a plastic bucket or plastic pump-up sprayer. Do not use a metal container.
  • Apply Thompson's® WaterSeal® Deck Wash liberally with a brush, roller or sprayer. If you are using a pump-up sprayer, use a coarse spray. In areas with heavy discoloration or dirt, apply a second coat and brush lightly with a broom. Immediately and thoroughly rinse any overspray or accidental spills with water, especially on metal to avoid pitting or discoloration.
  • Wait 5-10 minutes and then thoroughly rinse the surface with a garden hose, removing all residue. After rinsing the surface, be sure to saturate the ground around plants and shrubs with fresh water.

Clean Up

  • Rinse equipment and brushes thoroughly with water.