by Tom Shepherd, Contributing Editor
Hitting the deck with greener options
A decade ago it was all much simpler: CCA pressure treatment was the way to protect exposed wood from mildew, rot, and termites – that is, until the EPA decided to protect people from CCA.
Since then, the most popular alternatives have been ACQ and CA treated lumber. (If you need to brush up on your acryonyms check the glossary on page 13.) All these chemical treatments are designed to prolong the life of the wood, so any compromises – fastener corrosion, a greenish tinge to the wood, and the occasional safety advisory – were considered acceptable.
But manufacturers have a couple powerful incentives for developing less chemicalized preservative treatments. For one, products that suggest increased safety and reduced environmental impact can lead to green certification. For the other… well, copper can get pretty expensive.
One solution is to formulate a water-borne compound with copper particles that are no larger than a micron in size. Even with a reduced volume of copper, those smaller ‘micronized copper' particles can, theoretically, become more permanently imbedded in the wood's structure and thus provide long-lasting protection with significantly less risk of leaching to the environment.
Three years ago, Osmose introduced MicroPro Treated Wood to the U.S. market. Their MCQ based formula earned an Evaluation Service Report from the International Code Council and has since become rated as an Environmentally Preferred Product by Scientific Certification Systems.
Field test results performed to AWPA standards tend to prove the long-term effectiveness of micronized copper treatment towards preventing decay and termite damage. MicroPro began to have some impact in the market, both under their own name and from affiliated products such as ProWood Micro from Universal Forest Products.
Yet there has been some controversy. An advertising campaign mounted by competitor Viance last year suggested that MCQ treated posts fail to hold up under ground contact. However, a court order has now blocked Viance from making “unsupported claims” about MicroPro's alleged ineffectiveness; the court refused to issue a similar restraining order that Viance had sought to prevent Osmose from commenting on their dispute.
Meanwhile, a growing number of manufacturers are holding onto the micronized copper bandwagon. PhibroWood's Sustain, for instance, is a fully micronized copper (MCA) formulation which uses tebuconazol as a complementary preservative.
“Sustain offers advantages to consumers in that it has a high level of preservative permanence, plus it works very well at relatively low retention levels in the wood,” said David Fowlie, President of PhibroWood. “So you're really seeing the advent of a new technology coming in and offering excellent performance at lower preservative retention and rates.” Homeowners are eligible for a limited lifetime residential warranty against decay and termites.
As for its green bragging points, Sustain is Greenguard Certified and Greenguard for Children & Schools Certified, which means it may qualify for credits toward LEED and NAHB-Green certification. And according to Fowlie, that's been good for sales. “Greenguard is an ANSI certified independent program which certainly carries some weight with green specifiers and green specification programs,” he said. “It offers the retailers, the spec writers, and the builders an advantage from an environmental perspective. Sustain's market share has grown substantially over the last 12 months, both at the customer level that we sell to – which is the wood treaters – and to the end consumers as well.”
Phibro also offers a product called StabilWood Decking & Fencing which utilizes a wood stabilizer along with the Sustain MCA preseservative. StabilWood reduces the weather related expansion/contraction cycles of exposed wood that can lead to checking, cracking, and cupping. Both PhibroWood products are approved for contact with aluminum building materials.
www.phibrowood.com • 877-737-9663
Other wood preservative approaches are completely chemical free. In Europe, thermally modified wood has developed a larger following in recent years, and a growing number of companies are now offering heat treated options in the U.S. For instance, the technology behind Cambia Heat Crafted Lumber renders wood inedible to mold and insects while increasing its dimensional stability. “This is a relatively new concept for most people, so they wonder how the claims can be true,” said Gary Weinstein, Cambia's president. “Well, consider the fact that steel must be hardened, and all kinds of properties can be introduced by heating it and quenching it at various temperatures. Likewise, one reason people cook food is that it's a way of preserving it.”
The Cambia process starts out with wood that has already been kiln dried, then heats it to nearly 400 degrees in a partial vacuum – less than 15 percent oxygen. That process modifies the hemicellulose, the most water absorbent portion of the wood's structure. “By reducing the amount of hemicellulose, we're changing the wood so it's no longer absorbing or giving off water,” Weinstein explains. “When wood is dimensionally stable it doesn't cup or twist or warp or crack, and paint and finishes stay on the wood much longer.” The heat process also breaks down the wood's sugar and basically removes the wood from the food chain for mold and termites.
At the end of the Cambia treatment, the volatility of the wood – how it interacts with its outdoor environment – has been reduced, which means that the wood's tendency to decay naturally has also been reduced. “It's 75 percent more stable, but it is still wood and it can check in extreme weather,” said Weinstein. “What we're doing is improving the wood, not making it perfect. Still, to be able to improve it to that extent is really quite an accomplishment.”
In appearance, Cambia Wood most closely resembles ipe, but it's not as hard or as heavy. “On the other hand, it works easier,” said Weinstein. “You can put screws through it without pre-drilling. And unlike ACQ pressure treated lumber, there are no corrosion issues.”
Cambia Wood's price is comparable to composite decking and offers a 25 year warranty against decay. It's also available in FSC. The product line is supplied through 2-step distribution.
When it comes to preservative free performance, it's hard to beat ipe. “We have ipe on the Atlantic City Boardwalk that's been there for 40 years,” said Don Ernst, a LEED-AP in the Green Products Division of Timber Holdings International. “We've had pieces taken out and sent to the U.S. Forestry Lab and they've rated the wood's structural integrity at 95 percent. After 40 years!”
Their Iron Wood Deck Tiles are 12” by 12” by 1” thick squares that click together for use on decking, patios, balconies, or even indoors. A 24” by 24” variety is also available for use on green roofs. “The neat thing is you can make them all straight, make them all sideways, alternate them and make it pretty. And you can order it with or without FSC Certification,” said Ernst.
www.ironwoods.com • 866-895-2326
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