»Alte Stadt« und »Stadt der Techniker«. Die Zürcher Baubestand und seine planerische Erfassung

On first sight, and despite some obvious intrusions from the middle of the last century, the old town of Zurich seems to be preserved and well cared for. However, this convincing impression of an authentic historic building stock is the product of modern remodelling. In order to be passed on, the built heritage had to be assessed and defined as such, a process which necessarily brought transformations. Organised and systematic examination of Zurich's existing building stock in the 1930s generated a dispositif of building surveys, inventories and rehabilitation and conservation guidelines, all of which determined the course of the stock's ongoing maintenance and modernisation into the 1970s and beyond. Clearly, the interaction between observing and constructing built heritage is signified in the longtime use of the survey drawings. The records of the 1930s – held up as impersonal, objective and thus scientific – produced something new, the»old town« of the 20th century. Reproducible and easily accessible, the idealised view of Zurich's built heritage became a useful planning device for a regenerative process of rehabilitation and repair. Since the actual complexity and heterogeneity of the building stock undermined the implicitness of an »old town« in the making, the historic conditions and the stock itself were simplified, reduced and homogenised. Furthermore, the history of the continued use of the survey materials calls into question the common narrative of old town rehabilitation and preservation. It seems clear, for example, that the applied rationality of the process in Zurich was not in opposition to modern architectural and urbanistic activity of the time.