Cost vs. Quality
What is certain is that making WPCs and PVC products requires a careful mixing of ingredients not just for performance, but for cost. One way to do that is by literally trimming away some of what's produced. It's a principal reason why a lot of lower-priced composite decking is flat on just one side and scalloped on the other–you use less mix to create a board.
Polyethylene and PVC today typically are made from extracts of natural gas rather than petroleum, but pricing still goes up and down with the oil market. Added cost pressures have arisen from this year's earthquake and tsunami in Japan, which knocked some processing plants offline. You can supplement U.S. PVC production by getting it from China, but plants there make a dirty product that requires a lot of titanium dioxide to whiten it–and titanium dioxide is in short supply. Meanwhile the recession has slowed business at the flooring and cabinet shops that generate most of what becomes wood flour.
Advanced Environmental Recycling Technologies (A.E.R.T.) has found other ways to limit cost runups. It gets its plastic from recycled goods rather than virgin PVC, and over the years it has learned how to convert ever-lower grades of polyethylene into usable feedstock. (Trex also gets most of its plastic through recycling.) As for wood flour, generally the more finely ground it is, the more expensive it gets. A.E.R.T. uses relatively large flakes of wood. The result, however, is a rougher-looking board than its competitors.
But if you really want to scrimp, ultimately you need to examine your additives–the chemicals that make trim whiter, deckboards stiffer, cores less (or more) foamy, and surfaces less likely to fade in the sun or crumble. Like spices, a little additive can cost a lot. Bill Ross, vice president of sales at Fiberon, says that while wood flour can cost 10 cents a pound and virgin PVC a dollar a pound, an additive can set you back hundreds of dollars per pound.
Anatole Klyosov, a biochemist and former WPC executive, says several lawsuits this past decade involving WPCs appeared to arise from failure to use enough additives. In one case, he says, a manufacturer didn't add enough color pigment, thus leading to fading. Another case stems from a lack of antioxidants.
"I'm astounded that we sold as many boards as we did five years ago," one decking exec says. "Because five years ago, those boards didn't do what they promised."
Some manufacturers expect the number of lawsuits eventually will drop because of capstocks. Why? Think of an M&M.
Just as putting a hard candy coating around an M&M's chocolate core protects the insides, manufacturers say pouring a cap around a WPC center protects that core from what in the past has led to its demise. "Wood fiber is the root of all problems" in WPCs, says Peter Gallagher, manager of sales development at Polyone, a leading compounder of resins and additives. It's what in the board (that) is susceptible to bleaching from the sun, decay from the wet, and consumption from the mold, while tannins in the wood flour can get out and stain the composite.
Capstock's advocates regularly say that adding this armor coat to the board significantly improves its long-term performance. What they bring up less often is that using capstock could make it possible to slack off a bit on what's inside–there's no need to put in coloring there, for instance. Whether firms actually are cheapening the insides remains an open question that likely will take years of field testing to determine.
For its part, Trex maintains that the core of its capped decking, Transcend, is exactly the same as its uncapped Accents line. "We don't have the philosphy that you can junk up the core," says Kyle Lancaster, Trex's director of technical services.
Trex may be open on that issue, but it's close-mouthed on what's in its capstock–so private, in fact, that it won't even say whether the capstock is animal, vegetable, or mineral. It just calls it a "shell." You also can't learn more about the capstock by examining a patent; like the formula for Coca-Cola, Trex's recipe for the "shell" is a company secret.
Such secrecy is quite common among decking manufacturers. Examine Material Safety Data Sheets for most of the major WPC and PVC products in the business and you'll find that many list up to 50% of their ingredients as "proprietary." At least one doesn't reveal any at all. And a lot don't even reveal they put in any additives.(See How To Make Plastic Wood)
On the other hand, reading manufacturers' warranties can give you a sense of what these firms believe their products can do–in contrast to the advertising claims they make. Pick up a Trex brochure for Transcend and you'll see on the cover a boast that Transcend "Resists everything but stares." But then go to its 25-year fade and stain warranty, and you'll see language that makes clear its resistance is limited pretty much solely to permanent staining from food and beverage spills.
Meanwhile, TimberTech considers its warranty voided if you use a snow shovel on it. And Deceuninck's Solstice decking, whose brochure declares it offers "The best performance under the sun," warns that you won't get repaid if you spill and then leave plant food on the deck or your dog makes a deposit that goes unnoticed.
Pace is amused by the trend among manufacturers to giving warranties stretching 25 years and longer on products that only came out in the Obama administration. "They make a product and throw it up on the wall and if it sticks, they market it," he says. "Look at some of these decking products that failed. Why did they fail? There's no long-term test data."