Learn All About Decking Materials
An ample amount of deck space is essential for anyone who enjoys entertaining outdoors. If yours could use some updating—or worse, if you don't have a deck at all—you should contact a local contractor in your area so you can be confident that your deck is dialed in for maximum fun!
ImproveNet can connect you with up to four deck experts in your area for free! The only thing you have to do is choose which decking materials and fasteners you want your contractor to use. Not sure? Keep reading to make an informed decision about your deck!
Decks represent a transition from the house to the outdoors. They may be an extension of the house or a separate room linked to the house by a pathway. Before you start planning your deck, think about how you want to use it, as that will determine not only its size but also the materials that go into its construction. Deck materials falls into three primary groups: naturally rot-resistant wood, pressure-treated wood and man-made materials.
Naturally Rot-Resistant Wood
Redwood is still the leading choice for decks on the West Coast because of its availability, beauty, and durability. It is also reasonably priced, which is not the case if you want to buy it in the Midwest or the East Coast. It is naturally resistant to insect damage and decay and has a low shrinkage rate. It comes in three standard grades for decking.
Construction heart (often called con-heart or deck heart) is the most widely used because of its lower price and general good quality. Each board normally contains several knots in varying sizes. It is usually sold green or air-dried. B Heart contains only a few small knots per board. It is commonly sold green or air-dried, and will not significantly shrink. Clear All Heart is as expensive as it is beautiful. It has no knots or blemishes and is normally sold kiln-dried.
Cedar is another widely used decking material, particularly in the Northwest where it readily grows. The most widely sold variety is Western red cedar, but Alaska yellow cedar is increasingly prevalent. Cedar deck boards, like redwood, are cut from the heartwood only. Western red cedar is lightweight and soft. The wood is fairly brittle but more than strong enough for decking material. Alaska yellow cedar is stronger but shrinks more than red cedar as it dries. Both woods are quite soft.
Tropical forest lumber has become popular decking choices in recent years. They are strong and rot-resistant. One of the two most common types is ipé, which is a South American hardwood so dense that it will not readily absorb sealers. The other popular tropical hardwood is meranti, which is a mahogany grown in the Philippines and Malaysia. It is often lauan.
For decking with pressure-treated wood, a top choice is Southern yellow pine, which is available throughout the central and eastern sections of the country. In the West, hem-fir is the standard pressure-treated wood. Southern yellow pine is a strong, attractive wood that readily soaks up the chromated copper arsenate (CCP) used to preserve it. Although a yellowish green when first treated, the wood weathers to a soft gray in the sunlight. Hem-fir is a generic name used to label several types of wood that commonly grow side by side in the forest. These are hemlock, larch, and several types of firs. Because this species of wood does not readily absorb preservatives, the boards must be perforated as part of the injection process, which leaves the surface slightly marred. The finished product is brown or green.
Growing in popularity because of almost zero maintenance, synthetic decking includes composite wood/vinyl, vinyl, and fiber-reinforced plastic (FRP). All of these products are virtually impervious to weather, rot, or shrinkage. They are also all more expensive than wood decking. Composite wood/vinyl is a mix of wood fibers and recycled polyethelene. It is sold in both the 5/4-by-6-inch dimensions popular in the Midwest and East Coast and the 2-by-6-inch size for the West Coast. It can be cut and sawn just like wood. Vinyl decking is made from polyvinyl chloride (PVC) and is fastened to the substructure by clips rather than being nailed or screwed down. Fiber-reinforced plastic (FRP) is a strong material made by pulling continuous strands of fiberglass through a polyester resin bath. After the fibers are coated, the material is then pressed in a die for the desired shape, whether deck boards or rails. Any vinyl or FRP deck must be laid out to use full-width boards because this material cannot be ripped lengthwise without exposing the hollow interior.
To Seal or Not to Seal?
Should you seal a deck after it's installed? Yes, even if it is redwood, cedar, or treated wood. Technically you don't have to seal naturally rot-resistant lumber like cedar and redwood but they will last longer if they are sealed periodically. Even pressure-treated woods will benefit from some sealant and stain.
The two primary choices are water repellant preservatives and semi-transparent oil stains. Both of these penetrate the wood. Do not use paint or solid stains, which sit on the surface wood and will soon wear off. Water repellant preservatives contain silicon or waxes that soak into the wood. Many of them also contain chemicals to kill mildew, which is advantageous if the deck is in a damp, shady area. Semitransparent oil stains contain pigment that protects the wood. Look for types that state the stain is UV resistant.
The California Redwood Association recommends that redwood be sealed right after the deck goes down, even if the wood is still "green," or wet. This applies to cedar also. Green lumber will not absorb sealant as well as dry lumber but even some sealant will still provide necessary protection. Redwood and cedar decks will turn a silvery gray if exposed to sunlight regularly, but they can turn dark from rain, lack of sunlight, and old age.
Pressure-treated wood should also be stained because it will further reduce the likelihood that it will split and check. If the wood is still green and wet, let it dry for several months first. Some pressure treated decking lumber is already treated with water repellant. Typically, such lumber is labeled "Thompsonized." In that case, adding new repellant right away will not be necessary. Wait for about a year and then recoat it each year.
Wood decks have traditionally been fastened down with nails, and still are, but there are several good alternatives. Screws and hidden clips are now widely used.
Nails go in fast on decks, but there are some drawbacks. Even the best galvanized nails will eventually rust, and good galvanized nails will usually turn redwood or cedar black around them. Nails will also sooner or later work loose. Hitting down a popped up nail head does no good; it has to be replaced with a longer nail. If you do use nails, use hot dipped galvanized nails, or better, stainless steel nails.
Screws are a popular choice because they go in fast, do not need predrilling, and are strong. And if you make a mistake, they are easy to back out. Moreover, the deck screws are made from rustproof materials, such as stainless steel. Screws, like nails, should penetrate twice the thickness of the board being nailed. So if you have 1 1/2-inch thick boards, screws should be 3 to 3 1/2 inches long.
Clips are available in a variety of styles. They basically are attached first to the top of the joist and then to the underside of the deck board. Some clips must be attached from underneath the deck. Vinyl, plastic and FRP decking are never nailed down, but instead are attached by clips.
Rails are often used for the plastic, vinyl and FRP decking. The rails are commonly aluminum and are fitted on the joists. The decking is then fitted to the rails.
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