COMPARISON OF LABORATORY AND FIELD METHODS TO EVALUATE DURABILITY OF PRESERVATIVE-TREATED SHAKES

Environmental concerns and life-cycle requirements of treated wood pro ducts require methods that define the minimum amount of preservative t hat will be needed to protect products in use. This study illustrates the relative merits of three methods that are used to evaluate the dur ability of treated wood shakes. Severity of challenge from decay fungi is greatest in laboratory soil jar methodology, next greatest is in f ield modules composed of stacked shakes, and least is in shakes expose d on small sections of roof decks in the field. Small sections of roof decks allow assessment of stability, color, and other weathering char acteristics. Modules of stacked shakes allow opportunities to design f ield experiments to evaluate effectiveness of preservatives with a tes t unit that is conducive to decay.