OSB is an acronym for Oriented Strand Board. OSB is an engineered product made from wood; it is manufactured from trees such as Aspen Poplar or Southern Yellow Pine. The logs are cut into precise strands ranging from 3 1/2" to 6" long and approximately 1" wide. These strands are then dried, sorted, and mixed with wax and a waterproof binder and formed into sheets, which are oriented in cross-directional layers for increased strength. The layers are then pressed at a high temperature and pressure to form the familiar 4x8 sheets used in construction.