Abstract: An integrated prefabricated furniture system is provided for fitting-out a building room of the type having a generally open plan interior and having at least one utility source. The furniture system includes a plurality of horizontal beam segments interconnected in an end-to-end fashion to form a rigid overhead framework configured to be positioned above the floor surface. A plurality of overhead support columns each have an upper portion rigidly connected with the overhead framework, and a lower portion shaped to support the overhead framework on a floor in a freestanding fashion at a predetermined elevation above average user height. Each of the overhead support columns includes an interior support structure in a generally X-shaped plan-form defining vertical raceways between adjacent legs of the cross-section.