This paper describes the field performance of end-matched southern pine boards treated with either CCA type C or CCA type C containing an emulsion water repellent (WR) additive. Boards were either kiln or air-dried after treatment, constructed into decks, and exposed for over 3 years at Harrisburg, NC. During this exposure, matched boards were monitored for internal moisture content, cupping at midpoint, checking, and degree of nail pull. The CCA-only treated boards display rapid changes in moisture content, check width, and degree of cupping that was directly influenced by rainfall. Although boards treated with CCA and the water repellent additive are starting to lose the characteristic of surface water beading, the boards continue to show greatly improved in-service dimensional stability compared with matched CCA-only treated boards. The effectiveness of the water repellent additive in reducing physical degrade during service exposure is manifested in greatly reduced check development and nail pull when compared to the CCA-only treated boards.

Download document (449 kb)
free for the members of IRG. Available if purchased.

Purchase this document