Ground-contact durability of wood treated with borax-copper preservative

Abstract

This study evaluated the ability of a borax-copper(BC) preservative to protect wood exposed in ground contact. Southern pine sapwood stakes were pressure-treated with 0.9%, 1.4%, 2.3%, and 4.7% BC solution concentrations and placed into the ground at test sites near Mississippi, or Madison, Wisconsin. Untreated stakes and stakes treated with 1% chromated copper arsenate (CCA-C) or 1.1% disodium octaborate tetrahydrate (DOT) were included for comparison. Stakes were inspected annually for decay (Wisconsin test site) or decay and termites (Mississippi test site) and assigned a visual rating. The 2.3% and 4.7% BC concentrations were largely effective in preventing decay in Wisconsin but were much less effective in protecting the stakes exposed in Mississippi. Stakes treated with 0.9% and 1.4% BC concentrations performed slightly better than did DOT-treated stakes at both locations, indicating that even low levels of copper help to limit both decay and termite attack. As expected, the CCA-C treatment was highly effective at both locations. This study indicates that although pressure treatment with BC can extend the ground-contact durability of wood in northern climates, it may be better suited to protection of wood used aboveground.

Citation

Lebow, Stan T.; Woodward, Bessie; Lebow, Patricia K. 2007. Ground-contact durability of wood treated with borax-copper preservative. Proceedings, one hundred third annual meeting of the American Wood Protection Association ... St. Louis, Missouri, May 6-8, 2007 : volume 103. Birmingham, Ala. : American Wood Protection Association, c2007: pages 82-87.