Wood decks, if left to the ravages of nature, can quickly deteriorate from that clean, shining wood surface you so admired when your deck was new to a dingy, gray, mildew and dry-rot infested eyesore.
If the damage is mostly to the deck surface, quick relief is on the way with the cleaning and resealing methods I recommend below. Before you begin, though, you should take a look underneath to be sure dry rot has not found its way into your deck.
Checking for Dry Rot and Making Repairs
Dry rot is a fungus that forms in moisture soaked wood, most often in places shaded from sunlight. Left untreated it will spread and destroy the integrity of the timbers, leading to structural failure. Seek it out diligently. It will hide from you in places that are hard to reach, often beneath the deck where boards and timbers meet. Use a screw driver or similar tool to jab at wood, searching for the tell-tale cardboard-like texture that offers little resistance to your probing. Do not be fooled by painted boards that look sound. Dry-rot can hide behind a layer of paint and be difficult to notice until you probe.
Badly damaged supporting timbers and deck boards need to be replaced. If the damage is not severe you can chip away the loose wood fibers and apply a fungicide product such as Bora Care or Shell-Guard. Many people report great success with using anti-freeze to treat the affected area. If a significant portion of a timber is damaged, consider cutting out that part and replacing it with a tight-fitting plug that you epoxy into place. (Follow recommended safety guidelines when working with epoxy.)
Cleaning the Deck Surface
Even after a single season new decks, if not properly treated, can lose their original luster and turn a dingy gray. Ultraviolet rays are often the culprit. Grime, mildew and mold can also detract from the appearance your deck.
Before you start work on the actual surface cleaning, make sure your deck has proper drainage. Clean the cracks between the surface boards with a pressure nozzle on your garden hose. (As tempting as it can be, avoid using a pressure washer. Even if used judiciously the power of the spray can damage the soft fibers of the wood, giving your deck a grainy and fuzzy appearance.) Where stubborn grime remains in the cracks between the boards, use a putty knife or saw blade to clear the way for water to drain. This is especially important close to a house where winter snow can trap water and create a pool inches deep.
The next line of attack is to apply an oxalic acid-based wood cleaner such as Wolman DeckBrite Wood Cleaner & Coating Prep or Armstrong's Wood Cleaner. The oxygen bleach products do not contain chlorine and are safe to use around plants and animals. The main ingredient is hydrogen peroxide, sometimes in a liquid solution or in dry form with soda ash. As the solution soaks into the wood, oxygen ions break down mildew, algae, and dirt.Another approach, if you are dealing mostly with mildew, is to create your own cleaning solution with 3 quarts water, one quart of oxygen bleach, and a quarter cup of liquid dishwasher detergent. Use the ammonia free type. The oxygen bleach will kill the mildew and the detergent will aid in its removal.
After allowing the cleaning solution to stand for 10 to 15 minutes, scrub with surface area with a medium-stiff brush, either on a pole like a push broom or down on hands and knees if you're like me and you want to put your muscle into your work. The final step is to rinse it clean with a garden hose.
Apply a Quality Deck Sealer
Allow your deck to dry before you apply any sealer or stain. Then choose a day when you are confident that you will not have any rain for the next 24 to 48 hours. You should not attempt to apply stains or sealers over existing paint or stain because the sealer will not penetrate the wood. You can test this by sprinkling a little water on your deck. If the water beads and is still on the surface after 15 minutes, you will need to go back and remove the existing stain.
When it comes to choosing a sealant there are several things to consider. Natural oil sealants are not recommended because the oils turn deck green or black. Also the natural oils serve as food for algae and mildew. Most clear sealants will not provide much protection against UV ray damage.
Among the best choices are pigmented sealants since it is the pigments that absorb UV rays and diminish the discoloration so often seen on wood decks. An epoxy sealant, such as DEFY Epoxy Fortified, has chemicals that both deflect sun rays and absorb harmful rays. It is a water based formula that comes in various colors such as natural pine, cedar, and redwood. Tinted finishes add color without hiding the natural wood grain, while semi-transparent stains add more color, allowing some of the wood's grain to show. The semi-transparent stains provide longer protection than tinted finishes.
If you have grown tired of cleaning and treating your wood deck every few years, you may be ready to consider another option-paint. A great choice, but tricky to apply, is a new paint that is a blend of water-based urethane and acrylic resins, such as the Sears Weatherbeater Ultra. The advantage is that the coating will last for many years.
Although decks can require a lot of maintenance to keep them looking sharp, they also offer years of enjoyment.