All Decked Out
The vast array of outdoor decking materials available today is less bewildering when you've had a chance to size up what you need in your own backyard. From pressure-treated and naturally rot resistant wooden decking to composite, plastic and metal decking, it's important to know which materials work best in your climate and are best for you and for your family's lifestyle.
Of course, cost is also a factor in the choice. But if cost becomes the only guiding factor, chances are you'll end up with an outdoor deck that will at best leave you a bit unhappy with the finished project. And at the worst, the decking may have to be removed and replaced long before it wears out.
Location is an important factor in deciding which decking material is right for you. For instance, a deck located on the south side of the house will get a lot more direct sunlight than one located on the east or north. Thus the decking's heat retention and reflective qualities should be a consideration particularly in areas where summer temperatures in the 80s and 90s are common. Conversely, a deck located on the north side of a house will get little direct sunlight and be prone to the growth of mold and mildew. Choosing a decking material that's easy to clean will minimize laborious maintenance on a deck on the north side.
Traffic and lifestyle uses of the deck also play a part in choosing the right decking material. If the deck is going to be an end in itself, traffic considerations and the decking's durability will be of minimal concern. But if the deck is to be part of the daily traffic of entering and exiting your home, a more durable decking is best. Likewise, if you plan to barbecue on the deck frequently, it might be wise to consider the decking material's flammability and susceptibility to permanent staining from grease, drinks and food.
Decking materials today are either real wood or synthetic material that may or may not contain some wood. The availability of various decking materials varies by region, but those mentioned here can be ordered in most areas.
If dramatic design treatments such as curved planks and contrasting color schemes are high on your priority list, then synthetics should be the first material you check out.
Wood composites The most popular form of synthetic decking today is wood composite. As with other forms of synthetic decking, wood composites offer a uniform look to the finished deck and lower maintenance. But contrary to some advertising, composites don't look just like wood, nor do they really succeed in creating a no-maintenance deck. They also tend to be at least as expensive as decking made from high-grade, non-pressure-treated lumber, often more expensive. Still, they are worth considering. There are many more design options for composites curves, colors, patterns and the decking material will most likely outlast the framing.
Most composites are made from recycled plastic and ground-up waste wood. The exact proportions vary from one manufacturer to the next. All are available in the standard 5/4-by-6-inch decking planks, and some are also available in 2-by-6-inch decking planks. The latter are for decks with supporting joists 20 inches on center, rather than the standard 16 inches. Never use composites as support joists unless they are specifically designed to serve that function.
There are two basic approaches to making a decking composite solid and hollow. The solid version of composite decking is readily available and more closely mimics real wood. The hollow version is, of course, lighter weight than the solid version, and manufacturers say it's stronger, too. Both versions are applied like ordinary wood lumber, using standard tools like a circular saw, drill and screwdriver. And like wood, if you're not careful installing the planks, you can get split ends from overtightening the screws.
If possible, look for composites in lighter colors, preferably as close to white as possible. Dark-colored composites tend to heat up and hold their heat in bright summer sunlight, more so than ordinary wood. It's also important to install composites with the brushed or grooved side up, the smooth side down. The smooth side can be a pretty slick surface when it's wet.
Wood composites haven't been around long enough for wood research engineers to be satisfied they'll perform well over the long haul. But since their appearance about 10 years ago, wood composite decking appears to be holding up well in a variety of environments.
Plastics The same folks who revolutionized the plumbing industry with polyvinyl chloride (PVC) piping would like to change your approach to decking. If you can swallow an expense roughly double that of a western red cedar deck, the PVC people make a pretty compelling argument.
Although PVC decking ends the entire discussion of the basic material's ability to resist decay, there is a question of durability under the intense ultraviolet rays of the sun. Normally, those rays can at least break down the surface of PVC plastic, dulling its luster and giving it a chalky feel. But most PVC decking companies say they've solved this problem by coating the sun-facing side with a pure, beefed up layer of PVC coating designed to hold its luster for decades. The rest of the PVC decking plank is usually made of recycled PVC.
All PVC decking planks are installed in a way that leaves no fastenings showing. Different companies use different approaches to achieve this effect. But all the approaches are easily executed by any seasoned do-it-yourselfer with ordinary tools. Even better, the deck plank manufacturers also make matching hand rails, newel posts and balustrades, so the finished project looks very uniform. The decking planks are often available in a variety of colors, although white is advisable if the sun's heat is an issue for barefoot users.
Aluminum With attributes similar to PVC decking planks, aluminum decking costs more than a good rot-resistant wood but slightly less (by 10 to 15 percent) than the PVC alternatives. Moreover, some aluminum decking manufacturers offer a lifetime guarantee of their product, a promise that isn't made with any other material.
Depending on which aluminum decking you buy, the finished project may end up being a waterproof barrier. That's a good attribute for second-floor decks positioned over a first-floor deck. But around a pool, it's important to pitch the decking away from the water, mainly to keep surface dirt and oils from being carried along in the rainwater and into the pool. Aluminum decking is also installed with the fasteners hidden, and the job is best left to professionals.
In northern climates, aluminum decks have a tendency to get frosty, even when the surrounding lawn is not. On aluminum decks finished white, the frost is hard to see and may be easy to slip on. Aluminum decks are also a bit noisy if you have a teenager who likes to bounce a basketball on the hard surface. Most aluminum decking is designed to hold up in the salt air without corrosion.
Pressure-treated As the least expensive and most common decking alternative, pressure-treated lumber also has some drawbacks that must be considered carefully. Even if the material's environmental impact is of little concern, other shortcomings may lead you to consider another decking material as a better overall value.
From the outset, it's important to purchase premium-grade pressure-treated decking rather than standard or seconds. On the East Coast, most pressure-treated lumber is made from what is generally called Southern pine. This can be any of several species, including shortleaf, loblolly, longleaf or slash pine. Generally speaking, these pines grow quickly in areas that are farmed for lumber. Their rapid growth rate contributes to destabilizing what was once a lumber noted for its stability. Therefore, when used as decking, knotty pressure-treated wood moves, cups, twists and sometimes splinters as it dries out. The more knotty the decking, the less stable. It's therefore best to buy pressure-treated with as few knots as possible and with knots no bigger than a dime. Moreover, it's a good idea to buy pressure-treated that's been dried partially, because twists, splinters and other problems show up best in dried lumber.
Pressure-treated lumber used to be impregnated with chromated copper arsenate (CCA), a chemical that makes the wood inedible to insects and fungi. Concerns about the arsenic in CCA-treated wood caused it to be phased out and replaced by different formulations. The two most common replacements for CCA wood are alkaline copper quaternary (ACQ) and copper azole. ACQ contains copper and a quaternary ammonium compound. It comes in two different types: ACQ-B, which has a dark greenish-brown color and ACQ-D, which is light brown. ACQ-D is not as effective in penetrating difficult-to-treat woods (Douglas fir), but both can be painted or stained, unlike CCA-treated lumber.
With pressure-treated lumber, it's also important to pay attention to the wood's retention level. Wood treated to a chemical retention level of 0.25 pounds per cubic foot is adequate for decking. Pressure-treated lumber impregnated at 0.40 pounds is appropriate for lumber in contact with the ground. The lower retention level lumber is less expensive than the higher level. Pressure-treated wood requires a yearly application of a water-repelling deck sealer. As with other natural lumber products, pressure-treated decking feels cooler on bare feet than some synthetic materials.
For more information about pressure-treated wood, visit the American Wood Preservers Institute at http://www.preservedwood.com.
Untreated domestics If you like wood but you'd rather not have pressure-treated decking underfoot, there are excellent alternatives. But again, you have to be a bit careful with what and how you order.
Cedar is the most common domestic wood available for decking. Topping the list are white cedar on the East Coast and western red cedar, which is grown on the West Coast but regularly shipped east for the homebuilding market. White cedar is usually about 10 to 15 percent more expensive than pressure-treated lumber, while western red cedar is 20 to 25 percent more expensive. Both are considered highly rot resistant provided you get lumber that is cut solely from the heartwood and doesn't include any sapwood.
Sapwood in cedars, or any lumber for that matter, is easy to spot. It always occupies the edge of a plank and is lighter in color than the rest of the wood. In white cedar, the heartwood is light brown or reddish brown, and the sapwood is white. In western red cedar, the heartwood is medium brown or reddish brown, and the sapwood is yellow. In both cases, the heartwood will last at least as long as pressure-treated wood.
Redwood and sassafras also make good decking woods, although their availability tends to be localized to their growing area. Redwood is commonly available only west of the Mississippi, and sassafras is usually only available in the South. Douglas fir tends to be widely available, but it's not as rot resistant as the cedars and tends to carry a hefty price. Likewise with white oak, although its ability to resist rot is on par with sassafras and white cedar, and it's a better choice if the deck is going to face heavy traffic.
Untreated imports Several imported species make good decking at a price competitive with domestic lumber. However, import prices tend to be volatile. So what's inexpensive one year may not be the next.
For instance, a few years ago, Spanish cedar, and Philippine mahogany were all selling in certain areas of the East Coast for about the same price as local cedar and even western red cedar. Spanish cedar and Philippine mahogany are very rot resistant, easy to work with and good looking as they age. It is a little more difficult to work with but is hard and more durable in heavy traffic areas. Philippine mahogany is also sold under the names meranti and red lauan.
To find which inexpensive imports are available locally these days, check with a local lumber dealer. The salesperson will probably give you a price in board feet, which he or she should be able to covert to the linear-foot price normally found on standard 5/4-by-6-inch decking planks.
Installing a new deck with fasteners other than stainless-steel deck screws is a false economy. The fasteners for decks are rarely more than 5 to 10 percent of the total cost of the deck. Although a non-stainless fastener might save you half the cost of the screws, they will more than compensate for that savings in staining and corrosion problems within a few years. Contractors like to use stainless ribbed deck nails because they can be used in a nail gun and applied more quickly than screws. Deck nails work fine until you have to remove a plank or two some time in the future.
Decks should always be sloped away from the house, with a drop of perhaps an inch every 16 feet. Local codes may dictate another ratio. In any case, the slope will help prevent rot where the deck meets the house. Likewise, supporting joists should have an air space between them and the house or supporting posts. Otherwise, dampness can get trapped where the two are in contact and begin to rot any untreated wood and, eventually, treated wood.
Maintenance of your deck will depend on local weather, sunlight conditions, traffic, uses and your aesthetic sense. Many decks end up seeing little maintenance and survive just fine. But an annual deck cleaning and application of a stain/sealer will make it last longer and look significantly better until it needs cleaning again. Renting a power washer goes a long way toward making annual deck maintenance less onerous.
In the end, choosing the right decking materials and installing them properly will give you years of satisfaction and pleasure. For those who love the outdoors, a new deck is like adding a room to the house at minimal cost.Â
Ken Textor is a freelance writer based in Arrowsic, Maine.