Towards Urban Mining—Estimating the Potential Environmental Benefits by Applying an Alternative Construction Practice. A Case Study from Switzerland

Modern cities emerged as the main accumulator for primary and waste materials. Recovery of both types from buildings after demolition/disassembly creates a secondary material stream that could relieve pressure from primary resources. Urban mining represents this circular approach, and its application depends on redefining current construction practice. Through the life cycle assessment (LCA) methodology and assuming primary resources as step zero of urban mining, this study estimates the impacts and benefits of conventional versus a circular construction practice applied to various buildings with different parameters and the country-level environmental potential savings that could be achieved through this switch in construction practice—using the increase of the residential building stock in Switzerland between 2012 and 2016 as a case study and key values from the experimental unit “Urban Mining and Recycling”, designed by Werner Sobek with Dirk E. Hebel and Felix Heisel and installed inside the NEST (Next Evolution in Sustainable Building Technologies) research building on the Empa campus in Switzerland. The results exhibit lower total impacts (at least 16% in each examined impact category) at building level and resulting benefits (i.e., 68–117 kt CO$_{2}$-Eq) at country level over five years, which can be further reduced/increased respectively by using existing or recycled components, instead of virgin materials.