A mid-Atlantic area building materials dealer announced that its yards would no longer stock PT lumber that is not rated for ground-contact use. Maryland-based TW Perry says that it is replacing all of its above-ground UC3B-rated dimensional lumber, decking, and fencing with UC4A-rated products this winter, in time for the spring building season. The company also says that it will switch from UC4A (ground contact, general use) to heavier-duty UC4B-rated PT posts, which are suitable for severe environments and saltwater splash zones.

According to TW Perry’s treated lumber buyer Chris Purdy, the move will allow their customers to buy any piece of treated lumber from their yards without having to worry about what application the lumber can be used for. TW Perry primarily stocks Wolmanized micronized copper azole (µCA-C) treated lumber. The retention level for UC3B micronized copper azole is  0.05 pcf, while the retention level for UC4A material is 0.14 pcf. The retention level for UC4A material is 0.23 pcf.

As PDB reported last year, members of the American Wood Protection Association, or AWPA considered a measure that would have changed treating standards so that all lumber sized 2x8 and greater would be treated to ground-contact levels to ensure that lumber commonly used for critical structural applications would carry enough treating chemical to stand up to harsh conditions. That measure was voted down, in part because of concerns that higher retention levels would raise the price of PT lumber, but the AWPA is still considering changes that will address PT lumber that is placed close to the ground and/or wetted frequently.

Purdy says that the move will result in only a ‘marginal’ increase in the cost of their PT material. He also noted that several other dealers are ready to follow the company's lead, and that at least one other wood treater is recommending the move to their dealers as well.