Structures and change – Tracing adaptability based on structural porosity in converted buildings

Among the approaches of circular construction, the reuse of buildings can be considered the most desirable as it leaves a large portion of embodied carbon untouched. At the same time, it also minimises the energy effort of modifying, transporting or reprocessing the components. However, its underlying mechanisms and boundaries are largely understudied as convertibility and adaptability are currently at most rudimentary integrated neither into legal frameworks nor the architectural or technical design process in practice. In this paper, a new methodology is presented based on the models of Brand (1995) and Leupen (2006) to describe the adaptability of buildings as a function of their structure. The model also includes the circulation system and the specific areas of use. In the discussion of structurally determined usability, several concepts are introduced, such as structural porosity, pockets of use, diversity of pockets of use and diversity of circulation. The method is applied to three case studies that offer different adaptabilities due to their structural configurations. As the permeability or structural porosity of slabs significantly contributes to the usability throughout the structure’s lifetime, ribbed slabs seem to increase adaptability. Together with the spatial structural porosity of the grid, it proves to be a helpful criterion for good appropriability and convertibility. The method proved beneficial in understanding the dependence of the change of use on a given structural configuration. It helps to name the essential aspects, objectify them and make substantially different buildings comparable.