The term "WBP Plywood" (which stands for "Weather and Boil Proof") refers to the type of glue that is used to bond the layers of wood veneer together. This terminology has been superseded by the EN314 and EN636 classifications, which define the bonding quality of the adhesive and the standards to which the plywood will perform.  All of our general-use hardwood birch plywood sheet materials (made from birch veneers) meet level 2 under these classifications, which means that they are suitable for use in humid conditions, and can be used outside if treated with an appropriate preserver and sealer.