A Homeowner’s Guide To Composite Decking

After Trex introduced composite decking in the mid-’90s, it was kind of like Kleenex — the company’s name became synonymous with the product. And why not? They were the only game in town, and the idea was solid: taking waste wood byproducts and reimagining and reforming them into sturdy, attractive decking that outperforms wood. Today, dozens of companies are giving Trex a run for its money through innovation and process improvement.

In the last 30 years, the composite decking industry has exploded, so you’d be forgiven for needing help navigating the crowded field. Ahead, we talked to two decking experts to arm you with information, whether you’re DIYing your deck or hiring a pro. If you’re considering a new deck or you want to revitalize an existing one, here’s what you need to know about composite decking.

What Is Composite Decking?

“Composite decking is a type of outdoor flooring material, and a popular alternative to wood decking,” according to Corey Buescher, a virtual handyperson expert at Frontdoor, an app that connects homeowners with experienced technicians (including decking experts like Buescher). “It is also known as wood-plastic composite (WPC) and is made from a combination of natural and synthetic materials.”

Composite decking is generally a composition of wood flour (a byproduct of wood processing) and plastic mixed together, says Mike Reeder, brand president of Archadeck Outdoor Living, who ran a decking company for 15 years. Early composite decking stopped there, but “a lot of new technology involves sealing the outer perimeter with plastic to ensure the weather doesn’t penetrate the surface, and there are others that are made entirely of plastic,” Reeder says. Outer perimeter sealing is also called “capping.”

Buescher says the plastic components of WPC “can be either recycled or virgin polyethylene (PE), polypropylene (PP) or polyvinyl chloride (PVC). The plastic binds the wood fibers together, adding strength and moisture resistance.” Other additives include colorants and stabilizers to enhance the performance, appearance and longevity of your deck, plus reduce mold and mildew.

Types of Composite Decking

Ever since Trex started the composite decking revolution, companies like TimberTech/Azek, Fiberon, Deckorators, Fortress, Lumberock and others have each made their mark by putting their own unique spin on the product. Cali Bamboo, for example, manufactures composite boards using bamboo fibers instead of wood, and other companies use colors, textures and other distinguishing features to stand out.

No matter the materials and look, “most manufacturers use the good, better, best method to differentiate pricing,” Reeder says.

• “Good” includes traditional composite, aka wood flour mixed with plastic and no capping.
• “Better” is a composite wood flour and plastic mix capped with plastic PVC wrap.
• “Best” usually indicates all-plastic decking, according to Reeder.

Companies may have their own terminology to describe the three levels of decking available. You can also choose between solid and hollow composite decking.

“Solid boards are typically stronger and can handle more weight and impact,” Buescher says, while hollow ones are lighter and easier to work with. Hollow decking is often less expensive than solid boards due to reduced materials, but solid boards tend to look more like real wood.

Pros of Composite Decking

Because it’s a synthetic product, you don’t have to worry about warping, knots, splits or other defects when working with composite decking. Even better, you never have to treat for termites or carpenter ants because composite decking isn’t susceptible to insect damage. Here are some other benefits of composite decking:

• Low maintenance. Composite decking never needs staining, sealing or refinishing, Buescher says. “You really don’t have to do anything but a light cleaning a couple times per year,” Reeder adds. Soap and water work great; no special cleaners are necessary.
• Durable. Manufacturers take great pains to engineer products that outlast wood. “The latest technology on boards that are wrapped composites and pure PVC products have 30-50 year warranties, including a ‘no stain – no fade’ guarantee,” Reeder says. Hardwood and pressure-treated decking, on the other hand, may last 20 years if you’re lucky.
• Easy to install. “Essentially, there’s no difference in installation or labor to install” wood vs. composite, Reeder says, especially for top-down fastening. Hidden fasteners add to the labor cost, and Reeder says they are becoming increasingly popular. “The boards have a groove in the side that allows space for a hidden fastener.”
• Cost-effective. Composite decking is more expensive than wood upfront. Still, Reeder says, “People often justify paying more for composite than wood” because the costs of stripping and staining a wood deck, including your labor, are considerable over time.

Cons of Composite Decking

Composite decking is manufactured with recycled materials, but it isn’t necessarily a green building product. Some manufacturers have committed to reclaiming or repurposing old boards, but many end up in landfills. And because the plastic and wood are bound together, the breakdown is slow. Other composite decking drawbacks include:

• Higher cost. “Generally speaking, synthetic decking can be anywhere from 50% to 100% more expensive than pressure-treated pine,” Reeder says.
• Strength. Today’s composites are strong, but check the manufacturer’s recommended span limit (the space between decking joists) before building or replacing wood decking. Most deck joists are 16 inches on center, but some hardwoods can handle 24 inches — too far apart for composites. And you still need real, pressure-treated wood or metal to build a deck foundation.
• Heat retention. Buescher says composites can get hot in direct sunlight, making it uncomfortable to walk on with bare feet. If you’re in a hot climate, look for composite decking that doesn’t get hot, and consider planting shade trees or installing awnings or sails to cool your deck space.
• Expansion and contraction. Composite decking can be affected by temperature changes, and “improper spacing can lead to buckling or warping over time,” Buescher says, and requires careful installation to allow for movement. Capped boards are more water-resistant, but they’re also more expensive.
• Not wood. Despite including pigmentation and texturing, manufacturers can’t make composites look exactly like the real thing. “Generally speaking, if you are looking for a board that looks closer in appearance to real wood, those cost more,” Reeder says.

Tips for Installing Composite Decking

Composite decking installs just like wood, but Reeder and Buescher stress that it’s important to read the manufacturer’s instructions. It will tell you the right fasteners and tools to use, the required span of the joists and spacing requirements. Here are some specific pro tips:

• Check the weight. “Build a strong and level substructure to support the heavier weight of composite decking,” Buescher says.
• Use approved fasteners. “[I] suggest using manufacturer-approved screws or hidden fastener options,” Reeder says. Look for color-matched screws for a seamless appearance, Buescher says.
• Watch your spacing. “Leave appropriate gaps between boards (typically 1/8 inch to 3/16 inch) to allow for expansion and contraction,” Buescher says.
• Stagger joints. “Stagger butt joints for a more natural appearance,” Buescher says, and leave space between the joints to account for expansion. “Use double joists or blocking at butt joints to provide proper support and fastening.”
• Splurge on cutting tools. “Use carbide-tipped blades and drill bits for smooth cuts and clean holes,” Buescher says. Always cut and drill in a well-ventilated area to avoid inhaling dust.
• Watch the temp. “Install composite decking in moderate temperatures to reduce the risk of expansion and contraction issues,” Buescher says. “Avoid installing in extreme heat or cold to ensure proper alignment and fastening.”

About the Experts

• Mike Reeder is the brand president of Archadeck Outdoor Living, a design/build company that offers custom deck building and patio contracting. Before moving to the national side, Reeder spent 15 years owning and operating Archadeck in Columbus, Ohio.
• Corey Buescher is a virtual handyperson expert at Frontdoor, an app service that connects homeowners with virtual technicians so you can feel empowered to do your own home improvement projects and repairs.