Cleaning and Sealing Your Deck

If the water beads up or stands on the deck, your deck may not need sealing yet.

A water test is the easiest way to ensure that the wood can absorb sealer or finish. Sprinkle water on the deck. If it soaks in immediately, the deck can be sealed. If the water beads up or stands on the deck your deck may not need sealing yet.

When you are certain the deck needs sealer, lightly sand rough spots with a pole sander and 80-grit paper. Be sure to wear a mask so you will not inhale the sawdust.

UV rays penetrate 1/64" of wood, which causes graying. Apply a brightener and cleaner to restore the wood's natural beauty.

Deck cleaners help remove dirt, nail stains, algae, and mildew. If your deck is not brand new, always use a cleaner before applying finish.

Cleaners are available in premixed liquid concentrates. Carefully read the manufacturer's directions before using the material, and follow all safety precautions and warnings on the label. Use the water test to make sure the wood can absorb the cleaner. Wear safety goggles, a long-sleeved shirt and pants. Do not wear sandals or open-toed shoes.

1. Remove all deck furniture.

   Examples of sun damage to deck wood.




2. Sand splintered areas with 80-grit paper. Repair damaged boards.



3. Sweep off loose debris and clean between the cracks of the boards.



4. Wet surrounding plants and shrubs. Cover them with clear plastic.



5. For concentrated cleaners, follow the manufacturer’s mixing directions.



6. Some cleaners require the surface to be damp before applying, while others require the surface to be dry. Consult the product label.



7. Use a paint roller with an extension handle, a garden sprayer, or a stiff-bristled push broom to apply cleaner to the entire deck. Don’t allow cleaner to puddle in any area.



8. Speed up the process by having one person apply the cleaner and another person back roll the deck. Back rolling is a process in which one person uses a roller or broom to spread any puddles.



9. Keep the deck wet with cleaner. Do not allow cleaner to dry.



10. Scrub tough areas with a stiff brush or broom. Avoid using wire brushes or brooms. The bristles can break off into the wood and cause rust spots.



11. Allow the cleaner to soak into the wood. Soaking time is usually no more than ten minutes, but check the product instructions.



12. Rinse the deck thoroughly with a hose.
    
    



13. Wash equipment with soapy water. Rinse plastic with water and remove.



14. Allow deck to dry at least two days before applying a sealer.



15. Rinse the plastic covering the plants with a hose and remove it.

Make sure to choose a deck stain or sealer that will repel water, resist mildew, and prevent fading in high traffic areas. Sealers and stains are either water-based or oil based. Oil-based finishes tend to hold their color a bit longer, but water-based finishes tend to be more durable and last longer. There are four major categories of sealants and stains, listed in order below. Each contains increasing amounts of pigment. The more pigment you apply, the less wood grain and texture is visible, but the better protection you are providing for your wood.

• Clear water repellent often provides basic protection, including waterproofing, minimal UV protection, and sometime mildew growth prevention. Because these are clear or natural-look finishes, there is minimal amount of UV protection and the underlying wood will begin to gray within a few months. Performance ranges from 6 months to up to 2 years.



• Toner or Tinted water repellant very similar to a clear sealant, except additional pigment or color is added. This provides additional protection against sun damage, further delaying the graying of the wood. In addition, the additional color can help to restore the original look of the wood even if a small amount of fading has occurred.



• Semi-transparent stains contain additional pigment, providing subtle color while still showing the grain and texture of wood. These provide additional protection against water and sun damage, usually lasting for three or four years.
  
  When choosing a stain, remember that the finished color varies based on the wood itself. If you are applying a new stain over an old one, choose a color that is similar to or darker than the original. To allow the new coating to penetrate into the wood, the old coating should be adequately worn or thoroughly stripped. Try a small test-patch of the stain in an inconspicuous area to ensure the proper color and appearance.
  
  Redwood and cedar contain naturally occurring pigments called tannins that may bleed to the surface. On these woods, either use a dark-colored stain that helps to hide the tannin or use a wood cleaner that is specifically formulated to remove tannin stains. To maintain a fresh look, recoating may be done every two to three years.



• Solid stain provides the most amount of pigment or color, and therefore the best protection for wood. However, it also hides the wood grain, only allowing some of the texture of wood to show through. Because of the excellent hiding properties, solid color stain is often used for heavily weathered wood, covering up damaged wood fibers. There are often more color choices with this category, so an attractive alternative would be to select complimentary colors for the horizontal boards or railings and the vertical balusters or spindles. Performance is often 5 years or more, depending on the level of direct exposure to sun and weather, and the amount of foot traffic encountered.

When applying a sealer or stain, always read the manufacturers directions. Drying times differ based on air temperature and humidity. Before you start, check the boards for needed repairs such as split boards or popped-up nails.

Wear rubber gloves, close-toed shoes, a long-sleeved shirt and pants when applying finish or cleaner to minimize the chance of skin irritation. Also, wear safety glasses to protect your eyes from back spray.

Tip: Do not apply deck product in direct sun. The finish will dry too quickly and will not absorb into the wood.

1. Check the weather. Try to find at least two days of dry weather with temperatures between 50°F and 90°F.



2. Remove all deck furniture and plants.



3. Sand all grade stamps, marks, and splintered areas. The entire deck may require sanding with a pole sander or palm sander to speed up the process. Sand in the direction of the grain. Be sure to wear a safety mask so you will not inhale the sawdust.



4. Sweep off loose debris and clean between the cracks. Make sure the deck is dry.



5. Cover plants and shrubs with clear plastic.



6. Stir the sealer or stain thoroughly. Do not shake sealer. Bubbles will form in the finish.



7. Apply a thin, even coat of sealer or stain over a two- to three-board section with a paint roller with an extension handle or a sprayer. Two thin coats are better than one thick coat that does not properly adhere or dry.
   
   Do not allow the finish to puddle. To speed up the process, one person can apply the stain or sealer and another person can use a roller or broom to spread puddles and to work the finish into the wood, a process known as backrolling.



8. Repeat the above process for the entire deck. Use a paintbrush to apply the sealer/stain in corners and other difficult areas, such as steps, railings, end grain and cracks. A second coat is optional.



9. Allow the deck to dry completely.



10. Before disposing of rags, spread them out to dry completely. Heat generated from evaporating finish on a pile of rags can start a flash fire. If you are using latex stain, clean equipment with soapy water. If you are using oil-based sealers, clean with paint thinner or mineral spirits.



11. Rinse the plastic covering the plants with a hose and remove it.