Wood deck or synthetic lumber? Is PVC a definite no-no? Trying to find out if Trex Transcend has PVC, and if so, should I nix it?


Wood deck or synthetic lumber? Is PVC a definite no-no? Trying to find out if Trex Transcend has PVC, and if so, should I nix it?

Asked by Susan Mayne

Trying to find a low-maintenance product that is also low in toxicity. Looking at ipe and also at HDPE products. Just saw Trex Transcend, and although it is 95 percent recycled material, I have a suspicion that the top layer is PVC. Trying to confirm that with the company. Is that a potential health hazard?

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Cynthia Phakos's picture

Trex "Transcend" is the newest generation of composite decking. It is considered a hybrid material as it combines a PVC outer shell with composite decking.

I did call and write to Trex regarding the shell and the only information they would give me is that it is proprietary information.

  • The PVC inhibits staining, fading and mildew, and as it is a hard finish, protects against severe weather and heavy foot traffic.
  • The partial shell (on the top and 2 sides) allows the product to breathe and avoid surface separation.
  • The composite deck material is made of 95% recycled materials such as plastic (including plastic bags) and wood scraps; and requires zero maintenance.

A few of my "green" friends and "non-green" designer friends don't like the material, but for different reasons.

  • The "green" friends don't like it because it is a "monstrous hybrid," a mixture of materials that can never be separated, and once finished with its useful life as a deck material, will go into the landfill for what might be forever.
  • My "non-green" designer friends don't like the material because it doesn't weather and has an artificial look and feel. It has rounded edges and not the crispness of wood. If you have these sensibilities, then PVC or no PVC, Trex is not for you.

Polyvinyl chloride (PVC)

PVC, Polyvinyl chloride, is the third most widely produced plastic, following polyethylene and polypropylene. By 2016, it is expected to reach 40 million tons. It is used in construction because it is inexpensive and durable, a common use being sewage pipes.

In the past ten years there have been several studies on the negative health effects of PVCs.

  • Additives, also referred to as plasticizers, make the PVC flexible, and so it has been used for children's toys, automobile interiors, shower curtains, and also medical devices, e.g. IV bags.
  • The most harmful additive that I have come across in my reading is DEHP, which was banned for use in children's toys by the EU in 2006; the FDA also suggested that manufacturers eliminate its use in certain devices in 2002. Toyota, Honda, and Nissan have eliminated the use of PVCs in their auto interiors starting in 2007.
  • DEHP has been found to be leached from the products through mouth contact, through a liquid medium, and through offgassing.
  • As Trex is a flooring used in an exterior application, these issues would be considered moot.

From an environmental perspective, there are other concerns. Some authorities in Germany and the Netherlands have discouraged the use of PVCs not for these additives, but because the manufacturing and disposal of PVC creates emission problems and, when burned, PVC produces carcinogenic fumes.

I did call and write to Trex regarding the additives, and the only information they would give me is that it is proprietary information.

Adding up the pluses and minuses

In the end, one must weigh the alternatives. I can attest to Trex being long-lasting and zero-maintenance, as I have just refinished my redwood trellis but did not have to touch my Trex deck.

  • Given the effort of sanding the trellis with a mechanical sander and then oiling it with a product that offgasses VOCs (minimally), it is a tough call.
  • Trex doesn't look or feel like wood, but the grain of the molds and some of the colors give somewhat of a wood appearance. Some colors are more successful than others. I find that the gray really does have the appearance of a weathered wood deck that you would find at the beach.

I like my Trex deck, because it is made from recycled plastic and because it is zero-maintenance. I am neurotic about recycling, and so it works for me. I guess the question is -- will it work for you?

And so, as Kermit says, "it's not easy to be green."

UPDATE 4/5/11: After Cynthia submitted her answer to this question, she received replies to her calls and emails to Trex while researching this answer. A Trex Product Specialist wrote, "Our shell is a nine-element engineered shell with a proprietary formulation." Cynthia was also told by phone that this shell is not PVC, but what exactly it's comprised of is proprietary information.

UPDATE 4/7/11: Cynthia received email from L.C. Williams & Associates on behalf ofTrex stating that "Trex Transcend is 100% PVC-free." Accordingly, we have struck through references to PVC content in the Trescend product above.