Manufacturers still feel good about wood-plastic composite decking, despite slowing growth in the product’s market share. Slower growth, after all, is still growth. All the same, Trex and TimberTech, two of the leading composite manufacturers, have entered the vinyl decking market, too, with cellular PVC products. Trex’s product, Escapes, and TimberTech’s XLM line join Azek Deck from established PVC product manufacturer Azek Building Products.

Some industry observers have speculated that Trex’s and TimberTech’s moves reflected the manufacturers’ concern about the future of the wood composites. Both manufacturers deny the claims. Rather, the companies say, these products were created in response to growth in what is known as the ultra-low-maintenance segment of the decking market — a segment of products targeted at homeowners who want to put in as little effort as possible to keep their decks clean.

Both Trex and TimberTech are marketing the new products, their product directors say, as easy-to-clean, and stain- and mold-resistant. Azek also puts stain resistance at the forefront of its marketing materials, along with scratch resistance.

Tom Day, product director for XLM (an acronym for extreme low maintenance), says TimberTech projects that the ultra-low-maintenance market will carry a 10% share of the decking market by 2010. “As we looked at and segmented our market, there was an ultra-low-maintenance segment that looked like it was growing, and a product like Azek was really starting to garner some share. We felt we could get into that market really easily with [vinyl siding maker] Crane as our parent company.”

Azek itself anticipates as much as 20% market penetration, noting that the whole PVC decking category has grown at a compound annual rate of 60% since 2005.

Scott Fedor, product manager for Trex Escapes, agrees that while ultra-low-maintenance is growing enough to create a market opportunity, the new introductions do not signal a sea change in the decking industry. “We don’t see [PVC] as the future of decking,” he says.

Lighter, Less Dense, and Less Rigid

Both Escapes and XLM are similar in composition, consisting of a PVC foam core surrounded by a rigid cap. Because the boards are 100% PVC and contain no organic material, the manufacturers say, they are more resistant to stains as well as to mold and mildew growth, hence the low-maintenance appeal. Azek Deck’s Harvest Collection is slightly different, composed of PVC and a small amount of flax fiber without the outer cap, while the new darker colors use a rigid-cap technology. Azek also uses a unique formulation that, in combination with the extrusion process, offers a consistency and composition that allows it to be worked easily with standard tools.

In addition to allowing for soap-and-water cleanup, all three makers are also marketing their new PVC decking as being scratch- or dent-resistant. However, the boards tend to be less dense and less rigid than wood composites.

“The rigidity of the material is going to be somewhere around 50% of what a wood composite would be, just because of the fact that it’s a foam structure,” Day says. “The rigid cap really helps give it stiffness and a little bit of strength, but it still ends up being less than what a wood composite board would be.”

For installers, the lower density, as compared to composites, should produce an appreciable difference in the PVC products’ workability. First of all, the PVCs are far lighter than wood composites, as much as 40% lighter, Day says. And because the boards aren’t as dense, fasteners can be applied without pre-drilling, which should speed installation. “You can screw into the material very close to the edge,” says Azek vice president of marketing Brian Kincaid. “The consistency of the product and the fact that it won’t warp or crack also helps give a very finished appearance. The gaps are tighter, and you can picture-frame the deck to finish the edges nicely.”

Kincaid and Fedor add that PVC materials also can be heated and bent for additional design opportunities. “It’s much lighter than the typical wood-plastic composite,” Fedor says. “You can bend it, so if contractors want to add any stylized designs they can do that.”

Vinyl vs. Green

Some green building advocates have decried the decision to create new PVC-based products, given the controversy surrounding PVC’s health and environmental record. PVC-based products have been criticized for years by health and environmental advocates who claim that the volatile organic compounds (VOCs) contained in the material are carcinogenic. VOCs in certain products can be released if the product burns, as it might if its incinerated or happens to be in a landfill when a fire breaks out. To that end, Kincaid notes that, after being tested for flame spread and other characteristics, both Azek Deck and its sister product Azek Porch have been certified by the California State Fire Code for use in wildland urban interface zones. Both products are self-extinguishing, so they won’t burn on their own or keep burning.

But despite such distinctions and long life cycles of PVC products, the controversy over PVC intensified recently as the U.S. Green Building Council (USGBC), creator of the Leadership in Energy and Environmental Design (LEED) certification, wrestled with a decision to add a credit to its program for contractors who avoid PVC products. The USGBC decided not to add the credit because of a gap in the data and questions about the environmental quality of PVC alternatives. But the report concluded that factoring in landfill fires, “the additional risk of dioxin emissions puts PVC consistently among the worst materials for human health impacts.”

Day and Fedor both say that their respective companies stand by the record of PVC-based products and insist that the PVC controversy didn’t in any way enter into the thinking that went into the new product introductions.

—David Zuckerman is a freelance writer in New York. REMODELING associate editor Lauren Hunter contributed to this article.