Has your wood deck seen better days? When a natural wood deck is relatively new, it can be a beautiful, functional addition to a home, providing a stunning stage for outdoor entertaining, recreation and more. After a few years, however, sun and rain can take a serious toll on wood decking, leaving it grayed, cracked and weathered.
The good news is that cosmetic problems are relatively easy to handle. Reviving a deck is usually just a matter of spraying, scrubbing and finishing it with the right products – a project that can be done over a couple weekends.
Because the many different deck restoration products have names such as “deck cleaner” or “deck restorer,” check the ingredients on the label against the following information so you get the right products. Before starting on the whole deck, test it on an inconspicuous area to ensure it achieves the result you’re looking for.
1. Clean the Surface
Begin by removing all garden furniture, plants and paraphernalia from the deck. Then use a broom or leaf blower to clear the deck’s surface of leaves and debris. Using a putty knife, pry or poke out any debris or leaves that are stuck between the decking boards. Then sweep or blow off the surface again.
Buy a good commercial deck cleaner that removes mildew, dirt and oxidation (graying) – the best ones contain sodium percarbonate. Mix up a solution by following the directions on the label.
Wearing rubber gloves and safety glasses, wash the deck with the cleaner. Generally, you can apply this with a mop and scrub with a long-handled, stiff-fiber brush or spray it on with a pressure washer. If you scrub by hand, work in 4-by-4-foot areas, scrubbing in line with the wood grain and rinsing with a hose as you complete each area.
For a large job, rent a power pressure washer from a home improvement center or tool rental outlet. Be careful with it: The powerful spray can erode the wood’s surface. Adjust the pressure to 600 to 800 pounds per square inch and equip the wand with a 40-degree fan-tip nozzle. Move slowly but steadily, keeping the tip consistently more than 6 inches from the surface.
2. Strip Old Finish
If the deck has an old, oxidized, peeling or flaking finish, remove it with a deck finish stripper. Opt for the least caustic product that will do the job – some finish-stripping products are mild and biodegradable, while others are caustic and toxic. It’s best to buy a small amount and test it in a less noticeable corner of the deck first.
When using any finish stripper, wear protective clothing, rubber gloves and eye protection.
Before application, protect surrounding siding, surfaces and plants with plastic sheeting. Strippers typically may be applied with a synthetic brush, roller or hand-pump garden sprayer. Do not leave the stripper on the wood longer than recommended by the label. Rinse both the deck and surrounding plants thoroughly with water when its time to remove the stripper. If you have a pressure washer, use it for rinsing.
3. Remove Stains
If your deck has algae, mold or other stains, this is the time to remove them.
Non-chlorine oxygenated bleach (with trade names such as Stain Solver or OxyClean) will remove algae and mildew stains, and some oxidized deck sealers. These products are non-toxic to handle, biodegradable and environmentally friendly. They also clean and brighten the wood, but are not recommended for redwood or cedar because they may darken the surface.
If your deck is redwood or cedar and has algae, mildew or mold, opt for chlorine bleach-based (sodium hypochlorite) cleaners. These remove mold and mildew and lighten the wood. Chlorine can damage the wood’s fibers and destroy the wood’s natural color if used improperly, and it is toxic to plants and people, so it requires careful handling. Always follow the label directions.
Caution: Never mix ammonia – or detergent that contains it – with chlorine bleach, the resulting fumes can be highly toxic.
4. Restore the Wood
Use a commercial deck restoration product to remove aged, gray wood from the surface and revive the wood’s original color and beauty. Oxalic acid-based products, often found in deck brighteners, remove grayed surface fibers from wood and the dark tannin stains that can occur on redwood and cedar decks. They also neutralize the pH balance that has been heightened by deck cleaners, an important step before applying a finish.
You can buy these products pre-mixed, but buying crystals that you mix with water in a non-metallic container is more affordable. This acid is caustic, so always wear rubber gloves, safety goggles and old clothes when working with it.
Follow the label directions for mixing and applying, and rinse with water as indicated. Many products may be applied with a pump-up sprayer, roller or brush. Following application, rinse off with a garden hose or pressure washer.
The wood must dry thoroughly before you apply a finish.
5. Finish the Surface
Over time, ultraviolet radiation from direct sunlight compromises wood’s surface fibers and lignin – the natural polymers in wood that give it rigidity and resistance to rot. The result is a wood deck that looks dull, gray and haggard.
Moisture can be a problem, too. As wood goes through wet-and-dry cycles, it loses its natural oils and dries out, eventually cracking and splitting. In very damp climates, where wood seldom has a chance to dry out, mold, mildew and surface stains can occur.
To protect a deck, it needs to be finished with a sealer, stain or paint that rejects UV light and repels moisture. Choose a finish that is waterproof or water repellent, not just water resistant. Read the finish’s label to make sure it offers UV protection and, if your deck is in a damp climate, the formula should contain a mildewcide, which kills mold spores.
You can choose a clear sealer, semi-transparent stain, opaque stain or paint. Generally speaking, the best finishes soak into the wood rather than lying on the surface. Surface films, including paint, tend to show wear patterns, and they peel more readily so they require more frequent re-coating.
An oil or alkyd-based finish provides the best protection, but water-based finishes are easier to apply and clean up. Apply the finish in line with the wood grain according to label directions – typically using a pad or brush. The result should be a finish that ensures years of lasting beauty.