Forgotten resource, untapped potential – rediscovering Swiss natural stone as a load-bearing building material

Natural stone, recognised as one of the oldest, most resilient, and sustainable materials, has been largely overlooked in Switzerland’s transition to ecological construction methods. Current usages in architecture, often limited to facade cladding or interiors, generate considerable CO2 emissions due to intensive processing and long transport routes; however, if used in an unprocessed state, stone could achieve a markedly lower CO2 footprint. Despite its high compressive strength, only a minimal portion of the 300′000 m³ of Swiss stone extracted annually is used in load-bearing structures, with nearly 50% classified as residual waste. This research introduces two architectural strategies aimed at utilising the environmental potential of Swiss natural stone as load-bearing material. The strategies are based on observations in Swiss quarries and are introduced in this paper in four case studies, which were developed during two design studios at the ETH Zurich, Department of Architecture. The aspects extraction, processing, transportation, installation and disassembly are addressed in all four case studies. The first strategy employs large-format, minimally processed blocks, while the second incorporates residual ‘waste’. Both strategies focus on improving the efficiency of quarry operations while leveraging the ecological and aesthetic advantages of natural stone to its fullest potential.