Decks
Painting, Oil, Stain, Clear Finishes, Protecting Your Deck Against Critters, Cleaning Your Deck, Roof Deck

Natural wood that is not protected begins to deteriorate the moment it is exposed to nature's elements. The ultraviolet rays of the sun, moisture from rain and snow, and various fungi soon take their toll. Although not a part of nature, irrigation water (any kind of water, in fact) also can damage unprotected wood.

Fortunately, your wood structures can be protected by the use of a high-quality oil-base wood preservative. The wood structures we discuss are more difficult to protect than siding because each structure contains many pieces of wood, each piece having more than one side exposed to the elements.

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Painting
Unlike wood siding, wood in decks, handrails, fences, retaining walls, and other complex structures expose several surfaces of each piece of wood to the weather. With these structures, achieving a positive waterproof membrane with caulking, sealing, and painting is difficult.

For example, painting a gazebo could require caulking hundreds -- maybe thousands -- of connections before painting. To top it all off, the structure may prevent you from painting all the various sides of each piece of wood. Imagine, for example, how you would maintain the underside of a deck that lies 12 inches off the ground? You'd have to be pretty skinny to get under there to apply a coat of paint.

Partially painted pieces of wood create a real problem. Even if the unpainted side doesn't get wet directly, exposed wood can absorb moisture in the form of vapors rising from beneath. A painted surface on that same piece of wood can become riddled with bubbles, splits, chips, and peeling paint. After the painted surface has been compromised, it can no longer fully protect the wood, and in fact, the damaged surface becomes a contributor to further moisture attack.

Our advice: Don't paint unless you can cover all six sides of every piece of wood. In situations where pieces of wood are sandwiched together, and the joined surfaces can't be painted, then the pieces should be joined as one by thoroughly caulking all connecting joints. If all sides can't be reached, an oil or oil stain finish is best.

Because of the chipping, bubbling, and splitting normally associated with painted decks and handrails, we are reluctant to suggest painting. However, a painted deck can be beautiful. If you do decide to paint, keep the following in mind:

• Make sure that the surface is thoroughly clean and that the wood is dry. Go to extremes to get the wood clean: pressure washing, sanding, and detergent scrubbing.

• Remove all loose nails and replace them with the next larger size.

• Use a hammer and nail punch to countersink all nails. Fill the resultant nail hole with a high-quality, exterior-grade putty.

• Fill all other holes with a high-quality, exterior-grade putty. During application be sure to remove all excess putty. This will help to keep sanding to a minimum.

• Apply a high-quality polyurethane caulking at all joints.

• Prime all bare areas and puttied spots with a high-quality, oil-base primer.

• Finish decks with a high-grade, oil-base finish. Handrails can be finished with a good-quality, acrylic-base paint.

• Be prepared to recaulk and touch up paint every year.

Never paint a wood surface that has previously been oiled. The paint won't stick, and you'll have a mess on your hands forever. The best rule of thumb is to repaint painted surfaces and re-oil oiled surfaces. However, oiled surfaces can be painted and vice versa if you take the time to use a paint remover followed by a thorough sanding. Once the wood is oiled or oil-stained, even the most minute spots of leftover paint show up like a headlight on lover's lane.

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Oil, Stain, Clear Finishes

Oil
Oil doesn't last as long as paint, but it is easier to apply. Instead of laying on the surface like paint, oil penetrates deeply into the pores of the wood, preventing the attack of moisture from within. Oil also penetrates between joints and connections. For ultraviolet protection, fine wood preservatives also reflect or absorb ultraviolet rays.

With oil, there is no rigid surface layer (like paint) that can bubble or split. However, oil eventually evaporates out of the wood, leaving it unprotected. Oil takes 12 to 18 months to evaporate to the point where some areas of the wood may be unprotected. Wood that is protected with oil should be recoated every -- you got it -- 12 to 18 months.

Remember that horizontal surfaces (especially decks) are less forgiving than vertical surfaces (such as walls, posts, and rails). When used on a deck for example, excessive amounts of oil can puddle, and puddled oil doesn't dry. Puddling scuffs easily and can stick to furniture, feet, and shoes. This can mean the destruction of interior floors.

Stain
If you want to stain a deck, look for a product designed specifically for decks. Well-meaning do-it-yourselfers often end up applying stains designed for vertical surfaces, such as siding. Stains designed for use on vertical surfaces are not as abrasion resistant as those made for decks. Deck stains are made to resist scuffing where lots of traffic is expected.

A semitransparent, oil-base stain is a good bet. The combination of oil and a pigment protects the wood from both sun and water and hides surface irregularities.

Plan to spend in the neighborhood of $20 to $35 per gallon on semitransparent, oil-base stain. A gallon covers approximately 300 to 500 square feet.

For vertical surfaces, a semitransparent or solid color stain shows off the beauty of the wood. The solid color stain won't show as much of the wood as a coat of semitransparent, but the solid color protects the wood for a longer period of time. Some folks wrongly assume that solid color stain is like paint. A solid color stain definitely does a good job of showing off the grain.

Always apply an oil or oil-stain finish either early or late in the day when the wood is not in full sun. The thinner that helps the oil penetrate evaporates too quickly on hot days. The oil can end up laying on the surface.

Help to force the oil or oil-stain into the surface by going back over the entire area with a paintbrush or roller (called backbrushing). A China bristle or natural bristle paintbrush is by far the best applicator for use with oil. A nylon paintbrush should not be used with oils, oil stains, or oil-base paints. One to three applications of a high-quality product may be required.

Clear Finishes
If you like the natural color of the wood you want to protect and don't want to alter its appearance, try a clear finish. Just be sure that the clear finish that you purchase contains UV inhibitors to fight off an ultraviolet sunburn. One we know of is Penofin.

Beware of the popular "cure all" water seals. Many of these products contain petroleum jelly or paraffin, which offer minimal water protection and absolutely no UV protection. Furthermore, these products have little penetration and rapidly evaporate.

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Protecting Your Deck Against Critters
Dirt is a world filled with tiny little insects (and some big ones too) and lots of moisture. Wood and water don't mix, and wood surrounded by dirt for any length of time simply deteriorates.

Wherever possible, move dirt away from the wood. For example, a flower bed tends to grow higher each time it is mulched. After years of mulching, the dirt may come into contact with your wood deck. When this happens it's smart to remove enough soil to eliminate contact. Eliminating earth-to-wood contact also makes it more difficult for termites to make it into wood structures.

Wood that has been exposed to moisture in dirt can be treated with a pesticide (such as copper napthinate). One we know of is Copper Green, which can be applied with a brush or sprayed on. Pesticides also help deter termites.

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Cleaning Your Deck
Always keep a wood surface free of any debris. Leaves, pine needles, and dirt hold water and accelerate rot. An occasional sweeping is all that's required here.

You can also give your wood surfaces (oiled, oil-stained, or painted) a good scrubbing using the following formula:

• 1 cup of powdered laundry detergent
• 1/2 cup liquid chlorine bleach (if moss is present)
• 1 gallon of hot water

Add the bleach to the water. Although this solution is mild, be sure to wear gloves and eye protection. Work the solution into the surface with a stiff bristle broom or a nylon brush. Once scrubbed, completely rinse the surface with water.

Severely neglected oiled or oil-stained wood may require washing with a wood-brightening product. Look for one that contains oxalic acid. Apply the product with a nylon brush in accordance with the manufacturer's instructions. (Remember to wear protective clothing, rubber boots, gloves, and safety goggles to avoid injury.)

A thorough cleaning with a pressure washer saves on a lot of elbow grease and makes those hard-to-get-to areas, like handrails and trellises, easy to clean. Pressure washing natural wood that has turned gray can help remove discoloration and can bring the wood back to its natural color.

A pressure washer can be rented from a paint store or tool rental company. Use extreme caution when operating the device to avoid personal injury and damage to the surface of the wood.

If you plan to refinish the wood after cleaning, allow the wood to completely dry before applying the finish. Once dry, nail heads, which rise above the deck's surface, should be countersunk. One of the simplest ways to do this is by using a hinge pin removed from a door hinge. The hinge pin serves as an oversized nail set -- much easier for a novice to use.

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Roof Deck
A roof-deck, simply stated, is a deck that doubles as a roof, or vice versa. A roof deck has all the properties of a roof without the ugly appearance associated with most types of flat roofing. The two most common types of roof decks are:

• Decks where the top surface is not the waterproof membrane. The top surface is usually ceramic tile, stone, or plain, patterned, or textured concrete. A waterproof membrane lies underneath the finish surface. This is the prettiest kind, but a leak repair often requires complete replacement of the finish surface.
• Decks where the top surface is the waterproof membrane. These are the least expensive to install and maintain.

Finding a leak in a roof deck can take time, but it isn't difficult. Sometimes leaks don't occur at the waterproof membrane, but at adjacent connections. The ticket is to find out where the leak is coming from to determine whether a repair can be made.

Continuous L-shaped metal flashing creates a waterproof seal where the deck membrane meets a wall. Part of the L shape travels vertically, 6 to 8 inches up the wall (beneath the siding) while the horizontal part of the L-flashing protrudes 6 to 8 inches away from the wall (beneath the waterproof membrane). The membrane sticks to the flashing, which extends up the wall beneath the siding to ensure waterproof integrity between the horizontal and vertical surfaces.

Unfortunately, flashings do corrode and rust. However, you can get a flashing to last almost forever by regularly cleaning and painting it.

Scuffs, scrapes, and lime deposit build-up can cause a roof deck to appear worn and tattered. So can cracked and chipped grout. Also, leaves and other debris are not only unsightly, but can prevent proper watershed or clog a drain, causing water to back up into the house. Here are a few tips:

• For tile decks, repair cracks and gouges in grout and seal the entire surface with a high-quality silicone sealant. This won't prevent a leak, but the deck surface looks better longer.
• For stone decks, repair cracks and gouges in mortar and seal the entire surface with a high-quality silicone sealant. This won't prevent a leak, but, again, the deck surface looks better longer.
• Keep drains free and clear of debris to prevent flooding.