Whatever your feelings on composite decking, it's here to stay. The category continues to grow, carving out a larger share of the multibillion-dollar decking market every year. But the pace of that growth has slowed: Where the early years of this decade saw annual market-share gains of 30% (in dollar terms), between 2005 and 2006 composites grew just 18% in dollar terms and in single digits in volume terms, according to John Pruett, area leader for building products at Principia Consulting. Pruett says much of the slowdown can be attributed to a rise in manufacturing costs — Hurricanes Katrina and Rita took out Gulf Coast resin facilities, which led to higher prices. But a rash of product failures and consumer complaints have hurt, too.

Today, manufacturers are offering a greater diversity of composite products than ever before, including different wood-grain looks, colors, railing systems, and accessories; but prices remain high, and many contractors have yet to warm to the material. Though the market for composite rail systems still has considerable room to grow, Pruett says, there is uncertainty about when composite decking will reach a saturation point.

Another key question, Pruett says, is how long building products conglomerates such as Dow, Alcoa, and CertainTeed will continue to compete with the pure play manufacturers that currently dominate the market. Last year, the top three composite manufacturers — Trex, TimberTech, and Fiber Composites — accounted for 53% of the value of the $1 billion composite market.

Manufacturers say that composite decks look better than ever, and homeowners  are buying, but many remodelers say they still prefer wood.
TimberTech Manufacturers say that composite decks look better than ever, and homeowners are buying, but many remodelers say they still prefer wood.

HOW MUCH MAINTENANCE? Composites made huge gains in the early part of the decade by selling consumers on the idea of a maintenance-free deck. That claim, however, proved unfounded: Composites need to be cleaned and, in moist climates, sealed to reduce mold growth. A class-action suit brought by four New Jersey households against Trex resulted in a settlement, the terms of which prohibit the manufacturer from using the phrase “maintenance-free” in its advertising, as well as from claiming that its decks require no sealant.

Manufacturers now readily admit that composite decks must be cleaned and are, depending on the environment in which they're built, susceptible to mold and mildew growth. “It's low-maintenance,” says Trex spokes-woman Maureen Murray. “It's certainly not going to prevent the need for cleaning. I don't think any product that's outdoors could do that.”

Paul Bizarri, vice president of research and development at Timber-Tech, says his company and other manufacturers have made substantial efforts to improve mold and mildew resistance, replacing oak wood flour — which in some cases contributed to mildew growth through the bleeding of tannins — with maple. At the same time, he says, an effort is under way to lower consumer expectations and better educate distributors, contractors, and homeowners about the conditions that promote mold and mildew growth — essentially any climate other than California or the desert West and Southwest — and how to treat growth that does occur. For example, gapping, Murray says, is essential “so debris and water can fall through. Otherwise they accumulate in those little crevices and create a food source for mold and mildew.”

BEND, DON'T BREAK While mold and mildew might be the foremost concern for homeowners when it comes to composite decks, when you talk to contractors, the conversation doesn't end there. Though composites receive high marks for durability, many remodelers who regularly install them say these products still leave much to be desired, and fall short of wood in a number of areas including look, feel, malleability, and structural integrity.

“We really don't like composites, as a general rule,” says Chaden Halfhill, whose Des Moines, Iowa, company Silent Rivers is a full-service design/build firm that earned a reputation for its high-design decks. “We understand why it exists, but it's not as pleasant to use.”

As a designer, Halfhill finds that the physical properties of composites hinder his creativity because the boards are less easily manipulated to create custom details. “You can't do a horizontal detailing because you need a certain level of verticality for it to support its own weight. And it's a bit harder to manipulate the wood because if you cut it down, its integrity decreases. You're limited by the nature of the material. Structurally, it can only do certain things.”

Sean Leonard, a project manager at Silent Rivers, says he dislikes composites' weight and flexibility, which make the boards difficult to work with, particularly on a hot day when boards are even less rigid. In addition, Leonard says that the lesser structural integrity of composite boards has forced him to adjust some of his standard practices. For example, notching and counter-notching — standard when building posts and rails as well as elevated structures such as pergolas and arbors — actually weakens composite boards.