Cleaning And Preserving Wood Decks


According to reports by most major home improvement magazines, a deck is one of the 10 best ways to improve the value of one’s home. And, the value continues to appreciate provided the deck is well maintained. On the contrary, a poorly maintained deck will not only detract from the beauty of the home, but also may be structurally unsound and be cause for injury. Therefore, regular deck maintenance should be a part of the home improvement agenda for anyone with a deck.

Most decks are constructed of redwood, cedar, pine, or fir. While each of these will react differently to weathering, the maintenance techniques that follow will apply to each.

Studies by wood technologists with the U.S. Forest Products Laboratory show that ultraviolet (UV) rays from sunlight and water are the two primary forces that attack the integrity of wood decks. UV rays deplete the natural resins contained in the wood fibers causing it to turn gray and look washed-out. In addition, when water is absorbed into the fibers, the material swells and then contracts when it dries. The result is twisting and cracking.

Mildew and other surface residue hold water thus keeping the wood wet and causing rot to occur.

The secret to keeping a deck looking good is to restore its natural oils. Oiling the deck preserves the wood by protecting it from UV damage and by minimizing the amount of water that can be absorbed by the wood. Actually, oil in the wood’s fibers displaces damaging water — it’s that simple — oil in the wood is better than water in the wood.

Sound like a tough task? Not really, thanks to modern technology and an assortment of fine deck stains and wood preservatives. Before applying a deck stain or wood preservative the deck should be thoroughly cleaned to remove any existing discoloration or surface debris. The goal is to bring out the natural color and luster of the wood and, at the same time, open the pores of the wood to aid in the penetration of the forthcoming dressing.

There are two popular methods used to clean decks. They can be utilized separately or in combination with one another:

The first and least expensive method is sanding.

Use 80-grit to 120-grit sandpaper and a sanding block. An electric sander will make this task significantly easier. This method may be required for a deck where the wood grain has raised or where splintering has occurred.

When this method is chosen it is important to first countersink nails or screws.

The second and most popular method involves using a deck cleaning/brightening product. These products are simply wood bleaches that come in concentrated form. Look for a deck brightener that contains oxalic acid. We have found this ingredient to be the most effective in removing dark stains and restoring the natural color of the wood.

Dilute the concentrate with water in accordance with the manufacturers directions and apply with a garden-type sprayer. A second application and some scrubbing with a nylon brush may be required for badly discolored decks.

A note of caution: Deck brightening products can irritate eyes and skin. Be sure to wear protective clothing, rubber gloves and safety goggles.

Once the deck has completely dried, (at least a couple of days), apply a thin coat of wood preservative (a clear wood preservative is not as effective as one that contains stain). The stain acts to reduce UV penetration.

Having said that, whether you use a stain or clear preservative depends entirely upon the finish that you desire — since both offer protection. If the natural grain and color of the wood appeals to you, then a clear wood preservative will do the trick. These products contain water repellents, UV inhibitors and chemicals that prevent fungus and mildew. Clear wood preservatives that contain linseed oil are more environmentally friendly and offer an excellent finish. If you wish to enhance or slightly change the color of the deck, use a light-bodied oil-base stain. The oil helps to restore the natural resins to the wood fiber and the pigment offers some color that can be coordinated with other surrounding finishes.

The clear wood preservative and the oil-base stain are both applied in much the same way. Use a brush, soft cloth, or paint roller. Remember, the lighter the coat the better, since heavy coats cause sticky, gummy spots and an uneven finish. Moreover, be sure to apply the product in strict accordance with the manufacturer’s instructions. Applying the product when the weather is either too hot or too cold could end up being a disaster.

Chances are that a light touch-up at least once annually will keep that deck looking great and will be a splendid spot for some great weekend entertaining!


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