Pressure treating wood with waterborne preservatives is done to
counteract the harmful effects insects, microorganisms and fungal
decay can have on wood. But as of Jan. 1, chromated copper
arsenate- (CCA-) treated wood voluntarily has been removed by wood
producers from the consumer market in the United States and Canada.
The bastion of the treated wood industry since its development in
1933, CCA has joined the ranks of products deemed environmentally
incorrect by agencies such as the U.S. Environmental Protection
The replacements to CCA soon will become familiar by their
acronyms. The most commonly used alternative waterborne
preservatives are alkaline copper quatenaries (ACQ-C and ACQ-D with
carbonate), sodium borates (SBX) and copper azoles (CBA-A and
CA-B). There are some lesser used waterborne chemicals, such as
ammonial copper zinc arsenate (ACZA), and variations of the
previously mentioned compounds. Naturally weathering wood
alternatives such as redwood, yellow cypress and certain cedars are
environmentally acceptable but more expensive than CCA-treated
The consumer market generally uses treated lumber for decks,
outdoor furniture, gazebos, fences, railings, landscaping, and park
and playground equipment. The roofing industry's primary contact
with pressure-treated lumber is for wood blocking, curbs, sleepers,
batten strips and other integrated locations where a fastening
substrate is needed.
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