A.Merritt Kline, a product support specialist with APA/The Engineered Wood Association and the Southern Forest Products Association, and Bob Clark, an engineered wood specialist with APA, respond: According to the American Wood Preservers' Association (www.awpa.com), recommended preservatives for plywood and southern pine lumber intended for use in the construction of permanent wood foundations (PWFs) include .60 alkaline copper quat — types C and D (ACQ-C and ACQ-D) — and .31 copper azole — type B (CA-B) — in addition to .60 chromated copper arsenate (CCA).

Unfortunately, the Southern Pine Council's Permanent Wood Foundation Design & Construction Guide (which can be downloaded at newstore.southernpine.com/cgi-bin/newsopine/product?;32) does not address this new generation of waterborne treatments. However, there's no reason to believe that fundamental design and detail recommendations would be...

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