Composite decking claimed 22 percent of the US deck market in 2023, up from less than 5 percent in 2000, and the category is projected to keep growing as manufacturers close the gap between synthetic and real wood. The short answer to what is composite decking is this: it is an engineered board made from recycled plastic and wood fibers, designed to look like hardwood but resist rot, splinters, and fading without annual staining. Understanding how composite is made, what it costs, and where it falls short helps you decide whether to spend the extra money or stick with traditional pressure-treated lumber.
How Composite Decking Is Made
The core ingredients are ground wood fibers (usually recycled sawdust or hardwood flour) and thermoplastic polymers like polyethylene or polypropylene, often sourced from recycled milk jugs, grocery bags, and pallet wrap. Bonding agents, pigments, UV stabilizers, and mold inhibitors round out the mix.
The ingredients are heated, mixed, extruded into board shapes, and embossed with a wood grain pattern before cooling. The resulting board is about 50 percent wood by weight, 50 percent plastic, with a density higher than most hardwoods. Modern capped composite adds a polymer shell on the top and sides that resists stains and fading far better than first-generation uncapped products.
Capped vs. Uncapped
Early composite decking (Trex first-generation, TimberTech original) was uncapped, meaning the wood-plastic mix was exposed. Those boards stained easily, supported mold growth, and faded significantly over 5 to 10 years.
Modern capped composite wraps the board in a protective polymer shell that is factory-bonded during extrusion. This shell resists stains from wine, barbecue grease, and sunscreen that would discolor uncapped boards. Virtually every premium composite sold today is capped on at least three sides.
Composite vs. PVC Decking
PVC decking (AZEK, TimberTech AZEK line) is fully synthetic with no wood content. It is lighter, even more stain-resistant, and cooler underfoot in direct sun. Composite with wood content tends to be stiffer and feel more like real wood.
Premium composite has largely caught up with PVC in performance, and the price gap has narrowed. Choose PVC for poolside decks or hot climates where heat retention matters; choose composite where a real-wood feel matters more than marginal weight savings.
Top Composite Brands Compared
Four brands dominate the residential market.
- Trex: Largest market share, Enhance Naturals at $3 per linear foot, Transcend premium at $6 to $9
- TimberTech: Owned by AZEK, Prime Plus at $4 per foot, Legacy Collection at $8 to $10
- Fiberon: Sanctuary at $4 per foot, Paramount at $7 per foot with a realistic woodgrain
- Deckorators: Voyage collection uses mineral-based composite, lighter and cooler than polyethylene
All major brands offer 25- to 50-year structural warranties and 25- to 50-year fade-and-stain warranties. Read warranty fine print; coverage varies significantly by product line.
Real Costs: Materials and Install
Expect $15 to $30 per square foot installed for composite decking. Material alone runs $3 to $10 per linear foot for 1×6 boards, with premium lines commanding the top prices.
A 16 by 20-foot deck (320 square feet) typically costs $4,800 to $9,600 installed with basic railings, versus $3,000 to $5,000 for the same deck in pressure-treated pine. The premium over wood is real but the maintenance savings close the gap over 15 years.
Composite vs. Pressure-Treated Wood
Wood decks need sanding and staining every 2 to 3 years. A gallon of stain covers about 200 square feet and runs $45 to $80, plus labor. Over 20 years, a wood deck might incur $3,000 to $6,000 in maintenance costs and labor beyond the original build.
Composite needs only occasional soap-and-water cleaning. Over the same 20 years, material cost plus minimal maintenance usually comes out ahead of the wood-plus-refinishing total. Plus composite never splinters or harbors deck screws that pop up.
Heat Retention Issues
Dark composite decking gets hot in direct sun. Surface temperatures on black and deep-brown boards can exceed 140 degrees F on a 90-degree day, making barefoot walking uncomfortable. Lighter colors like sandy tan and gray run 15 to 25 degrees cooler.
Deckorators Voyage uses mineral composite instead of polyethylene and runs 20 to 35 degrees cooler than traditional composite in the same color. If heat retention is a concern, choose lighter colors, PVC, or mineral composite lines.
Installation Differences
Composite boards expand and contract with temperature more than wood. Gaps of 1/8 to 3/16 inch between board ends and 1/4 inch at perimeter framing are required to prevent buckling. Hidden fastener systems like Camo or Cortex create clean surfaces without visible screws.
Joists for composite decking need closer spacing (usually 16 inches on center, sometimes 12 inches for diagonal install) because composite is less stiff than dimensional lumber. Confirm joist spacing requirements with the specific brand before framing.
Environmental Considerations
Most composite decking contains 90 to 95 percent recycled material by weight, diverting millions of pounds of plastic from landfills annually. Trex alone claims to recycle over 400 million pounds of plastic film each year.
At end of life, composite is generally not recyclable curbside because the blend of plastic and wood is hard to separate. A 25- to 30-year lifespan minimizes that issue; the boards spend decades as decking rather than bottles or bags.
When Wood Still Wins
Composite is not always the right choice. Small decks under 150 square feet may not justify the upfront cost. Historic homes often benefit aesthetically from real wood. Budget-constrained projects still favor pressure-treated pine at half the installed cost. For porches, overhangs, or deep-shade decks where rot is less of an issue, cedar or redwood can last 20+ years with light maintenance.
Run the math for your specific project. For most new decks in sunny, exposed locations, composite comes out ahead over a 15- to 20-year window.
