Generally, construction of ceilings in office buildings and other commercial buildings consists of metal T-bars inverted and set at certain rectangular patterns, fastened together and suspended horizonally from the building structure by the use of metal hanger wires. Thus, is created a grid of metal "windows" or frames with horizontal ledges. Rectangles or squares of sound absorbing material about 1 inch thick are laid in the "windows" on the horizontal ledges creating an acoustical ceiling. The space above the acoustical ceiling is used to create a cavity or plenum space wherein certain building services are housed such as air conditioning ducts, plumbing pipes, and electrical wiring conduits and wires, as well as providing space for recessed lighting fixtures. Access to the plenum above this type of ceiling is by the tilting and removal of the acoustical tiles or panels.
Further refinements of the above ceiling have been designed and manufactured which conceal the horizontal surfaces of the grid or T-bar system. This is called a concealed ceiling system. Concealment of the T-bar system is accomplished by ship lapping the acoustical tiles where they rest on the T-bars and holding the adjacent tiles in the same plane by the use of rectangular splines inserted into slots in the edges of adjacent tiles. This system, however esthetically pleasing, makes it difficult to obtain access to the ceiling cavity above for maintenance purposes. Access doors are sometimes placed in the ceiling where entrance to the ceiling cavity is required. These doors are usually obvious and unsightly.
The ceiling system of this invention provides virtually complete access to the plenum above while maintaining the asthetic integrity of the ceiling. Access is simple, tiles are easily removed, remain undamaged through removal, and are easily returned to their proper position in the ceiling. Moreover less labor is required to install my ceiling than is required to install a conventional concealed ceiling system.