Using the roof as a parking deck has strong appeal to owners of all types of flat-roofed buildings. A variety of cast-in-place concrete systems is used in this "two-floor/one story" concept on projects that would otherwise have dead roof functions. Burdine's Dadeland Store in Greater Miami, Florida, illustrates particular commercial and economic advantages available to users of this concept. The potential for further expansion is an inherent advantage of the concept. Future conversion of the roof area into an enclosed second floor is usually anticipated in initial design. This one-way structural system, which uses a ribbed slab formed with pans, achieves economy through the re-use of standard forming pans. They produce inside dimensions of 20 to 30 inches and depths ranging from 6 to 20 inches, although other sizes are available. Special design provisions for pan joints have been established through many years of construction experience. Joists may have openings in the ribs to accommodate mechanical systems, and the slabs between the joists can readily accommodate duct openings or sleeves.