How to Maintain a Deck

One of the keys to good wood deck maintenance is giving it regular inspections for rot and seeing whether it’s structurally sound. When learning how to maintain a wood deck, summer offers a good time to inspect the deck’s condition, as the air is warm and dry.

• Be sure to inspect the wood where the ledger board meets the side of your house, and where the stairs contact the ground.
• As part of the deck inspection, wiggle or put weight against the railings to make sure they have tight connections.
• If you notice raised or exposed nails, pry them up and replace them with wood screws.
• Fill holes in boards with exterior wood filler.
• Replace any other hardware that looks rusted.
• Keep the deck swept clear, especially when leaves are falling in autumn.

Occasionally, it may be necessary to replace a broken or damaged board in your deck.

• Use a claw hammer to remove the old board.
• Cut or have a replacement board cut to fit. Choose the same type of wood and stain or coat to match the other boards.
• Install the replacement board using a power drill and screw drill bit. Expect the new replacement boards to stand out compared to the older, more weathered boards.

Tip: If you have multiple boards that need replacement, consider replacing all of the deck boards at once for a fresh, uniform appearance with structural integrity.

Part of deck care is giving a deck a good cleaning once a year. Consider scheduling it when temperatures are mild, such as in spring.

• Before cleaning, clear any deck furniture, toys and potted plants out of the way.
• Sweep the deck.
• Use a putty knife to remove any debris from between deck boards that a broom or scrub brush can’t reach.
• Clean the deck by spraying a biodegradable outdoor cleaner that removes mildew.
• Scrub with a stiff bristle brush, using an extension handle, if necessary.
• Then rinse the deck with a garden hose.
• Pressure washing is an option, but follow instructions to avoid damaging the wood. Use the pressure washer at a low setting with a fan spray nozzle, and check manufacturer’s recommendations for the wood type. Do not use a pressure washer on a composite deck, as it can damage the decking.

Tip: Clean wood railings by applying cleaner and scrubbing from the bottom up. Top-down scrubbing can splatter cleaning solution onto dry wood and leave marks. Bottom-up cleaning splatters onto an already wet surface.

If your boards need a new protective coating as part of deck maintenance, or have never had a protective coat, you should stain or seal them. A stain or sealant will improve the deck's appearance while guarding against the elements. Some types of stain or sealant require new application every few years for best results.

• Allow a new, unsealed deck to weather for 60 to 90 days before staining.
• Conduct a water drop test by pouring a few drops of water on a deck board. If the board absorbs the water, the deck definitely needs sealing for protection. If the water beads, the wood is already sealed and may only need cleaning, unless you want to change its appearance.
• Cover nearby plants or shrubs with plastic sheeting to make sure they don’t get spattered with cleaner or stain.
• Apply painter’s tape along where the deck meets the side of the house to avoid getting stain on your home.
• Use a paint scraper to remove loose paint or opaque deck stain.
• Use a stiff scrub brush to remove flaking stain or dirt.
• Before staining or sealing a deck, clean the deck as described in Step 3.

Tip: Do not use a metal brush on cedar or redwood, as the bristles may scar the soft wood.

If you plan to stain the deck, sand the surface before application to make the wood better to absorb the coating. Sanding also offers the advantage of creating a smoother, more comfortable surface less likely to have splinters.

• Use an orbital sander to remove any old gloss and smooth out any rough areas on decking boards.
• You may need to use a sanding sponge on the railings or balustrades.
• Use 60 or 80 grit sandpaper on the main deck boards, and use 80 or 100 grit on the handrails.
• After sanding, vacuum the deck thoroughly to ensure that dust does not settle on the new finish.

Safety Tip: Always wear a dust mask and safety goggles to protect your eyes when sanding treated wood.

Before applying a stain or sealant, make sure the deck has had at least two days to dry.

• Begin by applying stain or sealant to handrails using a paint brush or paint sprayer, starting at the top and working down to the deck surface.
• Use a natural-bristle brush to apply oil-based products and a synthetic-bristle brush with water-based stains.
• Then stain or seal the surface decking boards. Use a roller attached to an extension pole to spread the stain, and then back-brush it with a stain brush. Alternatively, you can use a flat pad applicator. This method is equally as fast as using a roller and requires no back-brushing. However, it is not as efficient for reaching the spaces between the boards.
• Let the stain soak according to instructions and remove excess with a rag.
• Stain needs time to absorb into the wood but dries quickly, so avoid applying the stain in direct sunlight.
• Porous wood may require a second coat of staining sealer for even coverage.
• Most decks do not require sealant on the underside, especially when made of pressure treated wood.
• Stay off the deck for at least 24 hours until it has dried completely.
• Remove painter’s tape and return furnishings to their desired place.

Tip: Work in small sections to ensure the stain’s color uniformity, proper coverage and the ability to start and stop with flexibility.

When reviewing how to maintain a wood deck, consider these deck care tips.

• Periodically rearrange your outdoor furniture, including planters, toys and grills, to prevent sunlight from causing mismatched color patches as well as water gathering beneath them.
• Avoid using rugs or mats made of natural materials, which can trap moisture. Plastic or synthetic ones are less likely to have this problem.
• Trim nearby bushes and trees to at least 12 inches from the deck to discourage moss, mold and rot.
• If your inspection finds boards that are warped or raised, smooth them with an orbital sander to make them level with the surrounding boards.
• When mixing a cleaning solution for extremely dirty wood, consider a lower proportion of water for a more concentrated cleaner. This may be especially effective for long-neglected decks.
• If using multiple containers of the same stain or color product, mix them together in a bucket to ensure that the color will be uniform.
• Consider applying a waterproofing solution with a pump sprayer. Apply the waterproofing solution directly to dry boards and let cure for 24 hours. Fill any cracks with wood filler, spackle or caulk, then sand until smooth.
• Most composite decking does not require sealants, but some can be stained with product designed for composites to restore or improve their appearance.