ABSTRACT
Frank Duffy proposed a layered approach to building, and identified four layers: The shell is the structure; the services are pipes, ducts and wires; the scenery is the internal fit-out; and the set is furniture, fittings and equipment. In one way, the layering approach needs some refinement: it is very likely that building services will need to be maintained or replaced before the finishes are changed, and finishes such as tiling could have a far longer lifetime than the services buried behind them. Commercial buildings often make provision for accessing services through access panels, suspended ceilings and raised flooring systems. However, services are still often buried in walls, tangled up with the structure or trapped in the building with no provision for removal and replacement. In traditional brick and stone buildings the structure and the facade are combined, and the services are often woven through all of the elements.
