The in-place advantages of floors and roofs made of concrete are well established: permanence, noise and fire control and structural stability to name a few. But the construction cost of most concrete floor and roof systems has limited their application in single-family and low-rise apartment construction. To overcome this problem, the Portland Cement Association has developed and perfected a floor and roof system which provides for integration and distribution (I/D) of mechanical, electrical and communication systems. I/D produces a structure similar in design to one that would result from the use of prestressed double-tees. It is a combination of cast-in-place concrete, permanent fiberboard forms and reinforcing steel that results in cavity spaces or troffers which can be used to carry air ducts, wiring, and plumbing. An important advantage of the I/D System is its inherent ability to accommodate mechanical systems that run counter to the direction of the troffer. The relatively low-cost fiberboard forms which become a permanent labor usually required for stripping and cleaning of forms. The underside of the form becomes the finished underside for the concrete and the approximately one-eighth of an inch thickness for the form can hold hanger screws and fasteners during placement of the concrete for later attachment of conduit. I/D permits efficient use of mechanical systems, quick installation of forms, steel, and concrete components with small crews, and installation of ceilings before non-load-bearing walls are put up. The in-place advantages are those normally found in concrete deck construction: vibration-free, no-squeak floors, interiors easily remodeled by moving partitions, good insurance ratings, and sound reduction.