OSB (Oriented Strand Board) is an engineered wood-based panel consisting of strands of wood, which are bonded together with a synthetic resin. The strands are pressed together in layers. The outer layer strands are generally oriented longitudinally in line with the panel length, whereas in the middle layers strands generally lie in line with the panel width.
Large and long wood strands make it easy to identify OSB wood (picture shown above). The orientation of the surface strands is not always visually apparent, especially in small cut pieces of panel. The main merits of OSB lie in the field of its mechanical performance, which is directly related to the geometry of the strands and their orientation within the panel. Although OSB is made up of relatively large strands of wood, its surface is relatively smooth and this can be further enhanced by sanding without losing the aesthetic character which is unique to OSB. OSB varies in colour from a light straw colour to a medium brown depending on wood species used, resin system adopted and pressing conditions employe.
OSB contains no knotholes, core voids or points of weakness making it the most ideal wood for wall and roof sheathing.