Treated-wood woes

Watch out for pressure-treated products

Pressure-treated wood is often used to build children’s play equipment.

Pressure-treated wood is often used to build children’s play equipment.

Photo Courtesy of UC Davis

Sustainable Space columnists Lori Brown and Greg Kallio are professors in the College of Engineering, Computer Science and Construction Management at Chico State University.

The right stuff
Selecting building materials is vital to sustainable design because of the environmental impacts associated with processing and transportation. Actually seeing how products are made might make us reconsider using them in our green buildings and homes.

Otto von Bismarck, a 19th-century aristocrat, once said, “The less people know about how sausages and laws are made, the better they’ll sleep at night.”

He’s right, but in my experience pressure-treated wood and particle board should be added to his list (although I’m glad I know the whole story). Pressure treatment is a chemical process in which wood is placed inside a closed cylinder. Vacuum and pressure are then applied to force preservatives into it. The chemicals help protect the wood from termites, other insects and fungal decay.

Toxic treatment
Pressure-treated lumber contains some of the most potent cancer agents, such as chromated copper arsenate, alkaline copper quat, micronized copper quat, copper azole and sodium borates. Classified as waterborne preservatives, these chemicals primarily are found in treated lumber used in residential, commercial and industrial structures. Chromated copper arsenate (CCA) contains chromium, copper and arsenic (yikes). The chemicals are what give treated lumber a green color, which goes to show that just because something is green doesn’t make it good for the environment!

When pressure-treated wood is exposed to the environment—or buried into the ground—it poses a threat to human health and the environment by allowing toxins to leach into the surrounding soil and water. Obviously, it should never be burned.

More than 90 percent of outdoor wooden structures are made with pressure-treated wood. It is used frequently for fences, raised garden beds, formwork for patios, borders, mow strips, decks, picnic tables, pet houses and even children’s play equipment. In fact, nearly all wooden playground equipment has been treated with toxic chemicals. This is why it is highly recommended that children wash their hands thoroughly with soap and water after coming in contact with it.

Other options
Alternatives to pressure-treated wood depend on the project. The best for outdoor applications—such as decks and play sets—is to use redwood, which is more expensive but never needs sealing or staining. Redwood’s aesthetic appeal is undeniably greater than other lumber and building materials, and its resistance to decay and insects make it well worth the added expense.

There are several recycled rubber and plastic garden borders on the market. For raised planters, you can use recycled wood and plastic lumber. Look for wood treated by TimberSIL, too. Instead of impregnating the lumber with a mix of nasty chemicals and heavy metals, this product is treated at very high heat with sodium silicate (glass).

Take the time
Locally, try talking to the good folks at Meek’s Lumber & Hardware. They offer several alternatives using composite materials for decking that resemble natural wood, have lower maintenance requirements and incredibly long lifetimes. It is possible to avoid using treated lumber; it just requires a little extra time investigating other options that are right for your project. For your health and the protection of our environment, consider it time well spent.