The ability of physical treatments to reduce checking in preservative-treated slash pine posts

Abstract

Single and double kerfing, center boring, and incising were applied to green, peeled, slash pine posts. Posts were air-dried for 10 weeks and assessed for the number of surface drying checks greater than 1.0 mm in width. Posts were then pressure treated with a chromated-copper-arsenate (CCA-C) preservative and exposed outdoors in a horizontal position. The number of surface weathering checks in the treated posts was assessed after 6 weeks and 1 year of exterior exposure. The length, width, depth, and volume of such checks was also quantified after 1 year. Single and double kerfing and, to a lesser extent, center boring were effective in reducing the number of checks in untreated posts after air-drying and there was significant correlation between the green mass or growth ring eccentricity of posts and the number of drying checks that developed. Kerfing and center boring also reduced the number of checks in preservative-treated posts after 6 weeks of weathering. After 1 year of weathering, kerfing reduced both the number and size of checks in preservative-treated posts whereas center boring reduced the size of the checks but not the number. Kerfing was significantly more effective than center boring in reducing check width, depth, and volume after 1 year of weathering. Incising was ineffective in reducing checking after air-drying or weathering and kiln-drying of unmodified controls after CCA treatment also failed to reduce checking. Show more