High Quality Content by WIKIPEDIA articles! Oriented strand board, also known as OSB (UK) and SmartPly (UK Ireland), is an engineered wood product formed by layering strands (flakes) of wood in specific orientations. In appearance, it may have a rough and variegated surface with the individual strips (around 2.5 by 15 cm (approx. 1 in by 6 in) each) lying unevenly across each other.