Service Life of Finishes on Smooth-Planed and Saw-Textured Western Redcedar Bevel Siding

By R. Sam Williams, William C. Feist

Previous information on the service life of finishes on western red cedar was obtained from studies of vertical-grained lumber from old-growth forests using finishes that are no longer available. From previous studies at the USDA Forest Products Laboratory (Madison, WI), the performance of finishes formulated prior to 1990 on saw-textured and planed western red­ cedar (Thuja plicata), redwood (Sequoia sempervirens), Southern Pine (Pinus sp ), and aspen (Populus tremuloides ) were reported. Others have compared the performance of paint systems on smooth and saw-textured plywood.

All architectural finishes for use in the United States were reformulated in the early 1990s to lower their volatile organic compound (VOC) content to meet air quality legislation. At the time this study was started, little informa­tion was available on the long-term performance of these low-VOC finishes. Nor had any work been done to compare the performance of these new low VOC finishes on flat-grained bevel siding from second-and third-growth forests.