There used to be lots of options for building decks and outdoor furniture; one could use teak, redwood, or a few other rainforest timbers that are rot resistant. but we chopped them all down, and were pretty much left with cedar and the horrid pressure treated lumber, where a sliver in your foot was an injection of chromated copper arsenate. But now Eastman Chemicals (who also gave us Tritan, the BPA free substitute for polycarbonate) brings us Perennial Wood, a new long lasting wood that has gone through a process of " acetylation". For the year's round of furniture shows including ICFF, Eastman worked with Appalachian State University to design furniture out of the wood. I particularly liked Eugene Duclos' combo bench and bike rack.
It was also short listed for the Material of the Year from Material connexion. Perennial wood explains what the stuff is:
TruLast Technology is a process called acetylation, which permanently transforms the wood’s cellular structure throughout by using heat, pressure and an organic compound to replace the water-loving (hydrophilic) groups in the wood’s cells with water-hating (hydrophobic) groups, which minimizes water absorption and the associated damaging effects.
It is a lot safer than copper and arsenic:
The process leaves no toxic substances within the wood. The organic compound, acetic anhydride, is used in manufacturing a wide range of products, from acetaminophen to artificial sweeteners (aspartame, sucralose) to toothbrushes, eyeglass frames, adhesive tape, tool handles, and LCD TV screens. Use of acetic anhydride leaves behind small amounts of acetic acid, which is also found in household vinegar.
It’s a beautiful, humble material that provides unique aesthetic and performance characteristics not currently available for the outdoor market. We were also impressed by the sustainability story and the fact that this wood is grown and produced here in the U.S.A.
TreeHugger readers have seen acetylized wood before, from Britain's Accoya, which was used to build a bridge in the Netherlands. It is only available in a few places in North America, while Perennial Wood is made from southern pine (no mention if it is sustainably harvested or not).
Let's hope that this is the beginning of the end for pressure treated lumber. More at Perennial Wood.