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Clean, Seal or Stain a Deck

Sunshine and rain take their toll on your deck. Learn how to test the wood, apply deck cleaner and deck stain or sealer. Then follow the steps to bring your deck back to its original beauty.

Tools & Materials

Items may be Special Order in some stores. Product costs, availability, and item numbers may vary online or by market. Paint colors may vary slightly from those shown. Availability varies by market for lumber species and sizes.

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Testing the Wood

water beading on sealed deck

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.

Applying Deck Cleaner

UV rays penetrate wood, which causes graying. Deck cleaners help remove dirt, nail stains, algae and mildew. If your deck isn't brand-new, always use a cleaner before applying finish. Lack of preparation is the most common reason for deck stains and sealers to fail. Don’t skimp on this important step.

Step 1

Remove all deck furniture and other furnishings.

Step 2

replace damaged deck board

Sand splintered areas with a pole sander with 80-grit paper. Repair or replace damaged boards. Make sure to drive in any popped nails first – or even better, replace them with deck screws.

Watch our video: How Do I Use Sandpaper?

Step 3

Sweep off loose debris and clean between the cracks of the boards with a putty knife.

Step 4

cover shrubs with plastic

Wet surrounding plants and shrubs. Cover them with clear plastic sheeting to prevent spotting with chemicals. Also cover siding with plastic or paper before staining.

Step 5

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.

Good to Know

Some cleaners require the surface to be damp before applying, while others require the surface to be dry. Consult the product label. For concentrated cleaners, follow the manufacturer's mixing directions.

Step 6

Keep the deck wet with cleaner. Don't allow the cleaner to dry. 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.

Step 7

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.

Step 8

Allow the cleaner to soak into the wood. Soaking time is usually no more than 10 minutes, but check the product instructions.

Step 9

Rinse the deck thoroughly with a garden hose or pressure washer.

Step 10

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

Step 11

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


Carefully read the manufacturer's directions before using the material, and follow all safety precautions and warnings on the label. Wear safety goggles, a long-sleeved shirt and long pants. Don't wear sandals or open-toed shoes.

Applying a Stain or Sealer

damaged deck boards

When applying a sealer or stain, always read the manufacturer's directions. Drying times differ based on air temperature and humidity. Before you start, check the deck boards for needed repairs such as split boards or popped-up nails. Here are some additional tips to make the job better.


Don't apply deck product in direct sun. The finish will dry too quickly and won't absorb into the wood.

Use the water test to check your deck every few months to ensure the sealer is repelling water.

Regularly sweep off debris.

If you have a brand-new deck made of treated lumber (as opposed to cedar or redwood), you should wait at least a few weeks before sealing it for the first time. This allows the wood to dry so the stain is absorbed.

If you've replaced a warped or damaged board, the new wood will not be the same shade as the rest of your deck. If you wish to stain immediately, use an opaque or semi-transparent stain to create a blended surface.

An alternative to stains or sealers is applying a resurfacer or restoration product. These finishes are like a very thick paint. Applied with a brush or roller, they cover deck boards and do not show wood grain.

Step 1

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

Step 2

Remove all deck furniture, plants and furnishings.

Step 3

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 won't inhale the sawdust. Drive in popped nails or replace them with deck screws. Replace any damaged boards.


Always wear a dust mask and safety glasses when cutting or sanding treated lumber.

Step 4

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

Step 5

Wet surrounding plants and shrubs and cover them with clear plastic sheeting to protect them. Also cover siding with plastic or paper before staining.

Step 6

Stir the sealer or stain thoroughly. Don't shake sealer. Bubbles will form in the finish.

Step 7

staining near home exterior

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 doesn't properly adhere or dry.

Don't allow the finish to puddle. To speed up the process, one person applies the stain or sealer and another person uses a roller or broom to spread puddles and to work the finish into the wood, a process known as back-rolling.

Step 8

staining railing

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

Step 9

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

Step 10

Allow the deck to dry completely.