Stain the pressure-treated wood using a paint pad applicator, which is easier than brushing a large deck or structure by hand and more accurate than using a pressurized sprayer. But the instructions clearly state, "Apply one coat only." Usually no more than one coat is needed. Strip off any old stain that may be on the wood. Coat 2 â Thin 20% with specified thinner. If available, you may also use a roller to first apply the stain, then work it into the wood with your brush. Step 8 Wipe the deck with a dry towel after the second coat, cleaning up any puddles. Many homeowners and even some professional paint contractors incorrectly believe âmore is better.â In order for an oil-based stain to be effective, it must be able to penetrate the woodâs surface. A protective polyurethane topcoat is a great way to seal your wooden deck and increase its longevity. To avoid âlap marksâ make sure that the leading edge is kept wet and that wet stain is brushed into wet stain. The second coat can go on a little lighter than the first coat, and will ensure good coverage and adequate penetration into the wood for weather protection. How many coats are required? 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. If the droplets sink in, the wood is ready to be stained. Pick the finish that you want and apply accordingly. Deck Defense is designed as a one-coat stain, although due to the deep penetrating properties of the product, it may appear lighter than expected. Unlike many top-coat sealers on the market today, it penetrates wood below the surface, coating the wood fibers at the cellular level, which creates a long-lasting, flexible, breathable barrier. Even if you decide not to stain your deck, you should always apply some kind of sealer to keep it protected from the elements. Allow to dry overnight. Working with the wood grain, apply an even coat of stain using a 4-inch brush. DO NOT APPLY 2 COATS. Coat 4 â Sand coat 3 lightly with 220-grit paper. Seal or Stain the Deck Boards . Expect the butted ends of lumber to accept more stain. Many parts of the deck are still tacky. There are several techniques you can use to apply a deck sealer. Let dry 24 hours. That depends upon what type of stain you are using. Coat 1 â Thin about 50% with the specified thinner. Are More Coats Better? Apply the finish to 10 to 15 square feet of boards at a time, then â¦ Let dry 24 hours. Otherwise, you risk having your deck rot out within the first couple of years. Coat 3 â Thin 10%. This is the sealer coat. A major source of problems for deck finishes is the over-application of the coating. SEAL-ONCE® MARINE Premium Waterproofing Wood Sealer & Stain is designed to protect & stabilize marine wood against water damage, salt water spray & decay. Before applying stain, make sure your deck has been cleaned properly. Clean with a deck cleaner and sand the surface to remove any loose wood fibres and contamination; ensure that the new coating soaks in evenly. Use a paintbrush to stain between cracks and problem areas. Sprinkle some water on the deck. Do not sand sealer coat before applying coat 2. Applying the sealer with a brush gives you the greatest control for the most even application and will ensure that you get the sealer not only on the deck boards but in â¦ For composite deckingâthatâs decking made from recycled plastic materials and woodâfollow the manufacturerâs recommendations. A one-coat application is recommended. Apply over coat 2 without sanding. On new decks, apply only one coat of oil-based deck finishes. When in doubt, follow the instructions written on the container. He applied two coats of (a brand of) clear sealer. If project requires more than 1 container, blend all containers together to ensure uniformity. HOW MANY COATS OF STAIN SHOULD I APPLY? Apply to small sections at a time (1â3 boards); start at one edge of the board and work end-to-end, following through to the end of the boards to avoid lap marks. This is especially true on older surfaces that have been exposed for long periods of time.