DELTA BUILDING PRODUCTS INTERNATIONAL LLC DELTA Wall Floor and Roof Systems combine the cost advantages of open web joists and precast concrete. Today's building market has many structural floor and roof systems available for multi-level construction. However, DELTA's precast systems offer a unique and innovative combination of advantages that will make it the right choice for your next project. DELTA provides a wall, floor and roof system that is structurally comparable to other concrete systems while providing open space for mechanical systems without additional framing and loss of headroom. The unique DELTA truss and composite connection with the precast concrete panels gives the DELTA Systems an advantage over conventional open web joist systems.