by David Goldstein

Last week, following publication of my column about disposal solutions for wood treated with preservatives, a colleague reminded me that I had ignored the best alternative to disposal. 

Recycling pressure-treated wood is not possible in local programs because toxins must be kept out of mulch and compost, and reuse is limited by concerns about breathing toxic dust from cutting and sanding treated wood. But “reducing” discards should be the top priority. 

Rather than removing and replacing pressure-treated wood, first consider repairs. If the framing is still strong, problems like warped, cupped, split or splintering wood can be fixed with some effort, while problems like loosening nails or faded luster can be fixed more easily.

The simplest aesthetic repair is power washing and wood staining. Over time, foot traffic, weathering and the sun’s ultraviolet rays will affect wood’s surface. For unpainted treated wood, you can bring back the beauty of the original wood grain. Manufacturers suggest applying a clear or semi-transparent stain containing a UV inhibitor and water repellent every year or two to maintain the beauty of outdoor wood. 

The easiest structural repair is replacing loose nails with screws. Screws have more holding power and can fix minor warping, cupping, or curving. Sanding can reduce high edges of weather-worn wood, but sanding treated wood requires a dust mask, safety goggles, and a shower afterward. An alternative to sanding may be turning over the board. 

Use building code-approved, corrosion-resistant fasteners and connectors suitable for use in pressure-treated wood, such as hot-dipped galvanized fasteners or stainless steel. Coastal areas of Ventura County, especially with saltwater spray, should use code-approved stainless steel fasteners and connectors.

Treated wood available in local home improvement stores is likely to be infused with copper azole. Copper prevents soil fungus from attacking the lumber and deters insects, including termites. Copper azole, manufactured by Viance, LLC, was standardized by the American Wood Products Association and is approved by the U.S. Environmental Protection Agency (EPA). It has taken the place of wood treatments of the past. 

In contrast, treated wood from over 18 years ago likely contains arsenic or creosote, and some wood still sold for industrial use contains these toxic treatments. Creosote-treated wood in your garden should definitely be replaced, and wood treated with chromated copper arsenate also raises concerns, according to FineGardening.com in its online Issue 15, which summarizes technical studies on the subject. Inorganic arsenic accumulates in living tissues, and the study cited shows arsenic “migrated from the wood into surrounding soil.” Although only samples less than three inches from the edges of the wood showed “higher than background levels of arsenic,” and uptake of arsenic into the edible parts of vegetables was also limited, concern remains because soil from various parts of a raised vegetable bed often spread during gardening. 

For a non-toxic alternative, Accoya®, sold by Chino-based Sierra Forest Products and Royal Plywood Company in Cerritos, treats wood with acetic anhydride. It releases only vinegar into surrounding soil, according to Daniel Trebelhorn, an Accoya spokesperson.Trebelhorn also claimed in an email to me that the product offered “superior dimensional stability, resistance to rot/decay” and warranties for 50 years above ground and for 25 years if in ground or freshwater contact. 

Ventura County Building Official Ruben Barrera noted not all alternatives are “standing approved” options. He said options would be researched and approved “if appropriate” in response to a proposal seeking a permit. Many uses, such as raised beds, do not require permits.

Non-toxic wood treatments are more expensive than conventional treatments, priced closer to redwood, another alternative to treated wood. Trex and other composite decking manufacturers also provide alternatives for wood decking. Although more expensive than treated wood, composites are long-lasting and made from recycled products such as wood fiber from cabinet and door manufacturers, carpet fiber, and film plastic from bags. As an added benefit, some of the plastic bags used by Trex at their Nevada factory are collected from Ventura County. 

 

For more information, visit:

www.trex.com 

www.accoya.com 

www.treatedwood.com

www.finegardening.com/article/does-pressure-treated-wood-belong-in-your-garden

 

David Goldstein, Environmental Resource Analyst with Ventura County Public Works Agency, may be reached at david.goldstein@ventura.org or 805-658-4312.