Hit the Deck

House & Home

Carrie Madren March 1, 2011

Decks are the quintessential outdoor living room―defined and tidy but open to fresh air and the sky. Whether you’re building yours from scratch or refinishing an old deck, consider making it a green project by using materials that don't degrade old-growth forests or emit volatile organic compounds (VOCs) and that use renewable (or recycled) resources.

Fake It

Composite decking lumber is often manufactured from recycled or reclaimed wood and plastic scraps. Trex manufactures composite decking and railing lumber made of equal parts reclaimed wood and reclaimed/recycled polyethylene plastic. The reclaimed wood comes from woodworking operations, used pallets and tons of sawdust. The plastic largely comes from recycled plastic bags.

GeoDeck composite decking is made from microbial-resistant rice hulls (the discarded outer husks of rice kernels), reclaimed paper byproducts and virgin polymers. Its hollow lumber design means it uses less material per foot. ChoiceDek is made with recycled wood fiber and recycled polyethylene plastic from milk jugs and plastic bags.

Among the benefits to composite decking is that it doesn't need to be sanded, refinished or painted. But there is an environmental drawback: Though composite decking is long-lasting, if it does outlive its usefulness, the lumber must be disposed of in a landfill, where the plastic will not break down.

Think of the Forest

Real wood decking, the classic choice, has green options. "I like real wood when I do construction," says Martin Holladay, the senior editor of GreenBuildingAdvisor.com. "But try to buy it from a sustainable source."

Look for wood that bears the Forest Stewardship Council (FSC) seal or other reputable certification, and you’ll get wood from a well-managed forest. The FSC is an independent, non-governmental nonprofit that promotes responsible forest management; its high standards make up the most rigorous certification system available. In 2009, over 100 million hectares of forest were certified to FSC standards, according to the council.

FSC certifies forests around the world, so you can find cedar and tropical hardwoods in addition to local woods. Choose wisely, and you can buy wood that requires no refinishing—the application of chemicals—in future years. Sustainably logged red cedar is a good choice in the West, Holladay says, while white cedar is a good choice in the East. Of course, the greenest lumber will be wood that was sustainably grown and milled close to your home.

"It's better to get lumber with a certification, but in some cases, a local logger might not have gone through the certification process, but still cuts down trees sustainably," Holladay says.

Keeping Up

Many people believe that wood decks require finishing every one to three years. According to GreenBuildingAdvisor.com, extending the life of wood products reduces the demand on forests for replacement timber. Regular treatments can keep your wood deck in good condition as well as prevent mold and insect damage.

One nontoxic wood preservative is borate, a water-soluble chemical that has very low toxicity—but you’ll need to add a water repellant to keep rainwater from dissolving the solution over time. Another option is thermally modified wood treatments that make lumber less tempting for insects and fungi. Organic pesticides can be used in both surface and pressure treatments, and are preferable to copper-based treatments.

Search online for green sealers to find preservation solutions for your wood deck. One green choice is Biowash Natural Deck Oil, a water-based mixture of natural oils (typically soy and linseed oil) that reflect harmful UV rays responsible for breaking down the lignin that holds wood together, or protective sealers from Eco Safety and Bioshield.

Or you can forego refinishing altogether. "Most people worry too much about refinishing decks, and putting any kind of finishing on boards is a questionable practice," says Holladay, who advises letting boards age naturally over time.

CONTACTS: Bioshield; ChoiceDek; Environmental Working Group; Forest Stewardship Council; GeoDeck; GreenBuildingAdvisor.com.