Buzz
A recently built deck at the rear of the house.
iStockphoto.com/Eric Honeycutt
It was once much simpler to decide how to build a deck. Would you choose wood — or more wood? Today, there are countless decking options available, some of which contain no wood at all. Why all these choices? It's part of our ongoing drive to make things better, simpler, and more convenient.
Wood decking, whether it’s treated pine, redwood, or cedar, has one thing in common: it requires regular upkeep. Sanding, staining, and resealing are yearly tasks for some, while others may go two to three years between maintenance.
In recent years, some savvy entrepreneurs, recognizing that many homeowners may prefer a low-maintenance option, introduced alternatives. In addition to vinyl and aluminum, plastic decking has also emerged. However, the biggest transformation has occurred in the realm of composite decking.
Composite decking is typically made from a blend of materials (mainly wood and plastic), engineered to mimic the look of wood. The wood used is often made from byproducts of the lumber industry, like sawdust, wood chips, and wood fibers, while the plastic can be derived from both virgin and recycled materials [source: Jones].
Manufacturers mix the ingredients, often incorporating pigments and preservatives. The mixture is heated, shaped into board-like forms, and then cooled. The resulting composite decking board tends to be heavier than wood, though not as strong. However, composite decking resists rot, won’t warp, doesn’t splinter, and doesn’t require painting, staining, or sealing.
Most composite decking will experience some color fading after installation. Homeowners are advised to regularly sweep their composite decking, promptly address any stains, and rinse it off twice a year, followed by a soap-and-water scrub [source: Decks].
Continue to the next page to explore the various types of composite decking.
Types of Composite Decking
Not fond of decision-making? Well, you're in luck because there are only two types of composite decking available: solid and hollow. Solid decking has a more wood-like appearance and is heavier than hollow decking. Due to its increased mass, solid decking expands and contracts more with temperature changes.
Hollow composite decking presents a more synthetic appearance. However, it won’t expand and contract as much as solid decking. Be cautious when handling hollow decking, as it's more vulnerable to damage before installation. Solid composite decking tends to be more popular due to its enhanced strength and closer resemblance to natural wood [source: Montenegro].
No matter the type of composite decking, it’s crucial that the material is treated with preservatives and antifungal chemicals. Untreated wood left outdoors will rot over time, with excessive moisture speeding up the decay process. Even though wood fibers and cellulose in composite decking are combined with plastic, it can still rot, according to the Forest Products Journal. Since most composite decking products contain at least 40% wood (and sometimes as much as 70%), a lack of preservatives could lead to significant issues. Some composites contain up to 70% wood content [source: Carter].
The preservative is incorporated with the wood during the manufacturing process. Some preservatives, such as zinc borate, can remain effective in composite decking for over 20 years.
In 2005, the U.S. Consumer Product Safety Commission (CPSC) issued a recall for composite decking manufactured by Kandant Composites Inc. due to the decking breaking down. The material deteriorated from prolonged exposure to heat and sunlight. The CPSC advised owners to inspect their decking for visible cracks and check if the surface could be scratched easily with a fingernail or a credit card corner. Kandant is no longer in operation [source: CPSP].
Composite Decking Material
There are three main types of composite decking materials: polyethylene-based, polypropylene-based, and nonwood plastics. Oil-based polyethylene and polypropylene decking contain some wood. The industry seems to be shifting focus from polyethylene composites to the more durable polypropylene-based products (which are generally stronger and less prone to expansion and contraction), or polyvinyl chloride (PVC)-based decking. These plastics have no wood content, resist staining, and do not absorb water. Advances in technology are allowing manufacturers to give all these composites the appearance and texture of real wood. [source: Descoteaux].
Several factors play a role in choosing the material for a composite deck, including cost, color availability, and a hidden fastener system. Composite decking tends to be more expensive than wood, although the cost varies depending on the product. Nonwood plastics are considerably pricier than real wood, are lighter than other composite options, and generally do not contain any recycled materials.
The color, texture preferences, location, and intended use of the deck will help determine the best product for your needs [source: Decks].
Some of the major manufacturers in the composite decking industry include ChoiceDek, EON, Epoch Evergrain, GeoDeck, LP Weatherbest, TimberTech, Trex, and Veranda. The industry is continuously evolving, with efforts being made to resolve common issues like staining, fading, and mold growth that composite decking has been known to experience. Here’s a breakdown of some of their products:
- CorrectDeck is made from a combination of hardwood fiber and polypropylene, with 80% of its content sourced from reclaimed or recycled materials. Its CX line features a top polypropylene layer that provides antimicrobial protection to resist mold and mildew. [source: Descoteaux].
- Cross Timbers composite blends oak with polypropylene for a stronger board, capable of spanning 24 inches between joists, further than most other composites.
- GeoDeck’s Tongue & Groove includes cellulose with reduced lignin content, which helps the product resist fading.
- Veranda decking has a unique combed finish on both sides of the board, giving buyers the option of two distinct looks.
- EON is made entirely of plastic and uses ultraviolet light inhibitors to prevent fading. The product employs a T-clip fastening system instead of nails or screws, giving the finished deck a sleek, clean appearance.
- Epoch Evergrain’s compression-molded decking looks more like real wood compared to other compression decking products, with a deep grain pattern.
- ChoiceDek’s polyethylene and recycled wood decking is both lighter and stiffer than other options, thanks to its ribbed design, which allows for better air circulation between the decking and framing.
- Many decking brands offer easy-to-install hidden fasteners. Latitudes Composite Decking features a hidden fastener system that automatically spaces the boards with the ideal gap [source: Montenegro].
For detailed information on installing composite decking, continue reading below.
Ensure the composite decking materials you're considering meet local building requirements by checking www.Decks.com, which maintains an approved decking materials list. Visit the Decks website for more details.
Building a Composite Deck
Although composite decking materials tend to be pricier than most types of wood, the installation costs are relatively similar. Both wood and composite decks share a common foundation of pressure-treated wood, yet the methods for gapping and supporting the decking differ between the two materials.
Note: There is now a plastic lumber option, USPL's TriMax, that can be used for structural purposes. However, unless the joists are oversized or spaced closer together, the deck may feel bouncy [source: Hardy].
Manufacturer guidelines will specify the appropriate gap sizes required for composite decking. Gapping is crucial, both between boards and between the decking and any adjacent walls, to allow for the natural expansion and contraction of composite materials. To calculate the number of fasteners needed for the installation, multiply the number of joists by the number of decking boards.
Composite decking is generally weaker than wood. If you're reusing the foundation of a wood deck to install composite decking, additional joists will be required. If you plan to install the decking in a specific pattern, like herringbone or tile, adjustments to the framing will also be necessary [source: Hardy].
Proper drainage and airflow are essential for preventing composite decking from deteriorating. When installing composite decking over a solid surface, you must create a sleeper system. The area beneath the deck should be sloped to ensure proper drainage, or you can install a drainage system like TimberTech's DrySpace, designed to channel water away from underneath the decking.
The type of composite decking you choose will influence specific installation aspects. For hollow decking, you must use a picture frame design or a starter strip to conceal the end of the first board and cover the fact that it isn’t solid. Additionally, hollow decking requires screws at each point where a joist intersects with the decking board [source: Descoteaux].
A final point to remember: Although most composite decking manufacturers offer warranties, they will be voided if the installation doesn’t strictly follow the manufacturer’s guidelines. Improper installation can lead to a compromised, unsafe deck that is no longer covered by warranty.
To explore further details on composite decking, check out these websites for more information.
Unlike wood, composite decking cannot be refinished, so it’s important to be cautious with paint, grease, and red wine. Clean up any spills immediately to prevent permanent stains. Also, avoid using colored chalk — stick to white only.
