FROM PROTOTYPING TO ALLOTYPING The invention of change of use and the crisis of building types

The chapter analyses the invention and the form of the discourse on building conversion as one particular instance of redefining what a technology is and how it operates. I describe a shift from expert defined closure to lay based openness and tinkering as a shift from prototyping to allotyping: Since the early 1970s, change of use and building conversion have become a central and fashionable discourse among architects and architectural theorists. Before the 1970s, buildings were understood as technologies, as 'society made durable'. The notion of building type was central to link a building to a given use. A bank was a bank because architects applied existing templates, prototypes, to turn a building into a bank. In the 1970s, suddenly buildings became flexible - discursively, since building conversion always existed: 'Building type' no longer was a meaningful link between a building and its use. A bank should not stay a bank, but become a hotel, a theatre or a flat, in short: an allotype. The chapter elucidate this central shift in thinking about buildings and reflects on the special case of allotyping buildings and how it continues to vex thinking about buildings.