Oriented strand board (OSB), also known as flake board, sterling board and appetite in British, is a type of engineered wood similar to particle board, formed by adding adhesives and then compressing layers of wood strands (flakes) in specific orientations. It was invented by Armin Elmendorf in California in 1963.
OSB/2 - Load-bearing boards for use in dry conditions
OSB/3 - Load-bearing boards for use in humid conditions
OSB/4 - Heavy-duty load-bearing boards for use in humid conditions