Before you begin

  • Do a trial test before application. Surface may darken slightly with application and color appearance is different when fully dry. Also, previous water repellent treatments may interfere with the penetration of this product. If your deck has been routinely treated with a water-repellent, substantial cleaning may be required. To test, clean deck and apply product by brush to a one sq. ft. area that has experienced either low traffic, rests under an eave, or is in a corner. Product should penetrate wood if surface is properly cleaned.
  • Do not apply if rain is expected within 48 hours. Also, temperature must be above 50° F and remain above freezing for 24 hours.
  • Cover plants and shrubs. If using a sprayer, move all objects that could come in contact with over-spray. Wet over-spray can be removed by flushing immediately with water. Dry over-spray can be removed with mineral spirits, paint thinner, or alternative paint remover products.
  • Do not use in below grade application where water pressure is a problem or on painted or recently stained surfaces.
  • Protect product from freezing. Do not store below 32° F. in case of accidental freezing, call The Thompson's Help Line at 1-800-367-6297.

Surface preparation

  • Wood surface must be free of all waterproofers, wood stains, paint and stains from dirt, mildew, mold and other contaminants. Prior to application, clean surface completely with a deck cleaner and/or pressure-washer depending on condition of deck and level of cleaning needed. See chart below to select the right wood cleaning product.

Cleaning Products

If you need to remove: Use:
Stains from dirt, mildew, algae & fungus and there is little or no trace of a residual finish Thompson's® Water Seal® Deck Wash or Oxy Multi-Surface Cleaner
Weathered waterproofers or semi-transparent stains in addition to stains from dirt, mildew, algae & fungus Thompson's® Water Seal® Heavy Duty Deck Cleaner or Wood Cleaner Concentrate
Stronger, difficult to remove waterproofers & stains, especially solid stains in addition to stains from dirt, mildew, algae & fungus Thompson's® Water Seal® Maximum Strength Deck Stripper or Wood Stripper Concentrate
On Redwood/Cedar/Hardwoods: Tannin staining and restore lighter color of these or other high extractive wood species and/or neutralize wood after using other cleaners or strippers in addition to remove stains from dirt, mildew, algae & fungus Thompson's® Water Seal® Deck Cleaner & Brightener or Wood Brightener Concentrate

  • Redwood, Cedar & Hardwood Cleaning Instructions: These woods have natural characteristics that require special treatment to enhance beauty and waterproofing performance. When cleaning, we recommend using a pressure-washer (water only) at 1200 psi. If this is not available, use a deck cleaning product followed by a Wood Brightener to restore natural color. Wait 48 hours after application of the Brightener to apply this product.
  • Power Washer: A power washer is a useful tool particularly in combination with a stronger cleaner when removing film-forming finishes or stains.
  • Thoroughly rinse surface and remove all excess water. After cleaning, wait at least 2 hours before applying product. Allow longer drying time (4 hours) on overcast or cooler days below 60° F. It is not necessary for the surface to dry completely before application of this product.


  • Do not use with other waterproofing products, as variations in the final appearance of the wood may result.
  • Do not thin.
  • Manually shake or stir contents for a minimum of 2 minutes before use. Intermix all containers (of the same color) to be used to assure color uniformity.
  • A small trial patch should be tried before application over the entire surface.
  • Apply using a paint pad or brush. Keep the leading edge wet and distribute waterproofer evenly to help avoid lapmarks and keep the color uniform. Work from top to bottom or side to side in small areas so that the leading edge remains wet at all times during application. If using a garden or pump-up sprayer, back-brushing (with paint pad or brush) will be required to even out the finish. DO NOT APPLY USING A ROLLER. Some nozzle openings of sprayers may be too small for this formula. DO NOT THIN. If clogging occurs, use paint pad or brush. If using an airless sprayer, it is recommended that tips 409, 411 and 413 be used. These tips provide adequate spray patterns while applying an appropriate amount of product to the surface being treated. These tips along with back-brushing provide proper results.
  • Apply only ONE THIN even coat. A heavier, or additional coat will NOT improve performance or appearance. DO NOT APPLY TWO COATS. Avoid puddling.
  • Tackiness will result if over applied. May also occur after application if overnight temperature falls below 50° F within 48 hours of application.

Clean Up

  • Clean brushes and equipment with soap and water. Dry product can be removed with mineral spirits, paint thinner, or alternative paint remover products.