How to Seal a Deck With Thompson's WaterSeal

Instructions

1. Prepare the Area

   Spray plants, grass, and other vegetation below or near the deck with water. Cover the plants with a tarp or plastic sheeting to protect them from the deck cleaner. Also cover windows, walls, or other surfaces directly below the deck to protect them from dripping sealer or stain.

2. Prepare the Deck for Cleaning

   Sweep the deck thoroughly to remove all loose dirt and debris. Shake or stir a deck cleaner product, such as Thompson's 3 in 1 Wood Cleaner, as directed by the manufacturer. Pour the cleaner into a garden sprayer.

3. Clean the Deck Railings

   Spray a small section of deck railing and balusters with deck cleaner, using the garden sprayer. Plan to clean small areas at a time so that you can scrub and rinse all of the wood before the deck cleaner dries. Do not let cleaner dry on the wood. Let the cleaner sit for 10 to 15 minutes, or as directed. Scrub the railing and balusters with a stiff, synthetic-bristle scrub brush to remove dirt and discoloration. Immediately spray the area with clean water, using a garden hose and sprayer. Repeat to clean the rest the of the railing.

4. Clean the Deck Boards

   Clean the deck boards, using the same techniques used for the railings, cleaning about 10 to 15 square feet at a time. Scrub the boards with a long-handled synthetic-bristle deck brush. Work backwards from one far corner of the deck, finishing at a door or stairs, so you can exit the deck without walking over the cleaned areas. Let the deck dry for at least 48 hours. If you covered grass or other plants, remove their protective covers while the deck dries, to prevent killing the plants.

5. Check for Loose or Raised Fasteners

   Inspect the entire deck for loose or raised nails or screws, and drive the fasteners below the surface of the wood with a hammer and nail set or a drill. Also remove splinters or other potential hazards, using a sharp utility knife or sandpaper. Wipe away all sanding dust thoroughly. You can perform this step while the deck is drying after cleaning.

6. Seal or Stain the Railings

   Apply sealer or stain to the deck railings, following the product directions; application methods vary slightly by product. A paint pad works well for the broad faces of railing and the balusters, while a paintbrush is best for corners and tight spots. You can also apply a sealer or stain with a garden sprayer. Apply an even coating of sealer or stain to all surfaces, working in small areas and maintaining a wet edge (do not let the sealer or stain dry before moving to the next area). After completing each area, inspect the finish for drips or pooling, and redistribute or wipe up all excess with your application tool or a clean rag.

7. Seal or Stain the Deck Boards

   Apply sealer or stain to the deck boards, using the same techniques used on the railings and your choice of applicator: paint pad, paint roller, paintbrush, or garden sprayer. Apply the finish to 10 to 15 square feet of boards at a time, then wipe up any excess with a rag or your applicator. Work from the far corner of the deck to an exit point. It's usually best to cover a few boards at a time, working down their entire length, then working on the next few boards in the opposite direction. Let the sealer or stain dry for 24 to 48 hours (or as directed), depending on the product and conditions, before using the deck.

Deck Sealing and Staining Tips

Thompson's WaterSeal products typically need only one application, but you can apply a second coat of stain to darken the wood, if desired. However, you must wait for the first coat to dry (typically about 2 hours) and apply the second coat within 4 hours of applying the first coat.

Follow the manufacturer's recommendations for refinishing your deck every one to three years, as needed. Deck wood stays in much better shape if it is regularly maintained. Letting it go for an extra year or two usually results in permanent damage that shortens the life of the wood.