Plywood is widely used as a substrate in engineered wood flooring (EWF) construction. While the Canadian EWF industry largely relies on Baltic birch plywood (BBP), the development of an alternative substrate is clearly desirable.

The objective of this study was to evaluate the long-term performance of EWF made with an oriented strand board (OSB) substrate designed to deliver a higher than normal internal bond. Three-layer OSB panels were made from a mixture of 90 percent aspen (Populus tremuloides) and 10 percent paper birch (Betula papyrifera). Three adhesive configurations were used in the manufacture of specialty OSB panels: 100 percent liquid phenol formaldehyde (PF) resin, a mixture of 60 percent liquid PF resin and 40 percent powder PF resin, and 100 percent polydiphenylmethane diisocyanate (pMDI) resin. The performance of these three specialty OSB products was studied. Five types of substrate were used in the manufacture of EWF: BBP, sheathing OSB, and the three specialty OSBs. A polyurethane adhesive was selected to bond the surface layers to the substrates. The result of this experimental study indicated no significant difference between the long-term performance of the OSB substrate made with pMDI resin and that of the BBP substrate.