WoodSolutions Technical Design Guide 31 presents designers, specifiers, builders, code officials and certifying authorities a design procedure based on AS 1720.1:2010 Timber structures Part 1: Design methods for composite timber floor structures, manufactured using EWPs such as laminated veneer lumber (LVL) and glulam and fabricated into 'T or box beam 'cassettes'. The notations throughout this document are based on AS 1720.1. This Design Guide complements WoodSolutions Design Guide #30: Timber Concrete Composite Floors.