The Green Outdoors

With summer in the air thoughts turn to outdoor projects. In the past, many people relied on CCA (Copper Chromium Arsenic) pressure treated lumber for projects such as decks, garden planters, and outdoor play sets. Yet research suggests that over time arsenic can leach into surrounding soil, creating a health risk particularly for children. CCA has now been replaced by ACQ (Alkaline Copper Quat), which is certainly preferable from an environmental perspective. There have been some concerns about the leaching of copper affecting marine environments, and some green building professionals still recommend caution when combining pressure treated wood and vegetable gardening.

Recycled plastic lumber

Variations on recycled plastic as lumber have been with us for over a decade. While the original products tended to have a faux-wood look that had questionable aesthetic properties, the industry has came a long way, and consumers now have a wide range of options, including different colours and grain patterns. But it is not only the aesthetics that should guide which products to choose. The Healthy Building Network completed a study in 2005 comparing various plastic lumber sources, and the environmentally preferable options tend to have high recycled content and avoid PVC (preferred brand names include Eco-Tech, PlasTEAK, and Perma-Deck Advantage). PVC lumber and decking is problematic due to the high level of dioxins released to the environment. Dioxins are a known carcinogen as well as a suspected endocrine disrupter.

For the full Healthy Building Network Report see

Forest Stewardship Council cedar

Cedar has always been one of the best choices for exterior applications. It is naturally rot resistant, looks great, and anecdotally keeps the mosquitoes away. Unfortunately forestry practices associated with cedar, particularly on the west coast, have been controversial to say the least. In response came Forest Stewardship Council (FSC) certified wood — the only certification program for wood recognized under LEED. FSC certification is an independent guarantee that your wood came from sustainably managed sources. Finding FSC-certified decking can sometimes be difficult so be sure to ask for it at your local building store, or visit to find local sources. As an important note of clarification, most environmentalists only support FSC as opposed to more industry-friendly certification programs such as the Sustainable Forestry Initiative (SFI).

Environmentally friendly preservatives

An additional alternative is to use untreated lumber and apply your own environmentally friendly preservative. Eco-House, a Canadian supplier, provides a natural oil-based finish called Utah Woodsafe that they claim is safe for garden applications. It turns the wood a dark brown colour, but avoids any synthetic chemicals. Valhalco, another Canadian manufacturer, creates a unique plant and mineral based wood preservative called Lifetime Wood Treatment that has been lab tested to confirm no soil or water contamination. Lifetime Wood Treatment is designed to be a one-time application and has been used extensively in demanding environments such as Banff National Park.

For more information visit

Rodney Wilts is a sustainability consultant heading Loop Initiatives ( He has a background in environmental law, and was founder of Canada’s first green building supply centre. He can be reached at [email protected]

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