Patent 7326456 was granted and assigned to Alberta Research Council on February, 2008 by the United States Patent and Trademark Office.
A low density oriented strand board has an average density of less than about 1.5 times the density of wood species used in the board and a homogenous vertical density profile. Low density OSB may be formed by preheating the wood finish prior to pressing, controlling the moisture content such that the core layer has a higher moisture content than the face layers, or a combination of pre-heating and moisture content control.