The shearing layers concept views buildings as a set of components that evolve in different timescales; Frank Duffy summarized this view in his phrase: “Our basic argument is that there isn’t any such thing as a building. A building properly conceived is several layers of longevity of built components.
The concept is based on the work of ecologists and systems theorists. The idea is that there are processes in nature, which operate in different timescales and as a result there is little or no exchange of energy/mass/information between them. Brand transferred this intuition to buildings and noticed that traditional buildings were able to adapt because they allowed “slippage” of layers: i.e. faster layers (services) were not obstructed by slower ones (structure).
The concept of shearing layers leads to an architectural design principle, known as pace-layering, which arranges the layers to allow for maximum adaptability