Beyond Reinforced Concrete: Exploring Low-Carbon Foundation Alternatives Through a Case Study Approach

The construction sector’s growing contribution to global emissions underscores the urgent need for a shift toward carbon neutrality. Foundation systems, often made from energy- and resource-intensive materials, are a significant source of embodied emissions in new buildings. Previous research by the authors indicates that foundation systems can account for up to 68% of the total embodied fossil emissions in carbon-negative buildings. This paper presents a catalog of buildings that have explored alternative foundation systems, utilizing minimally processed or recycled materials, with a focus on drastically reducing or eliminating concrete and steel. These case studies are grouped into three categories: stone and timber foundations, gabions, and natural cement/limecrete casting. A comparative Life Cycle Assessment (LCA) covering life stages A1–A3 is conducted. Key findings show that above-ground foundations, especially those incorporating timber, offer carbon-negative solutions, while gabion foundations can significantly reduce the environmental impact, even when used as below-grade solutions. The paper also examines the context behind these design choices, considering factors such as ground properties, seismic class, and building characteristics. The study demonstrates that low-carbon foundations for low-rise buildings are feasible when geological and geotechnical conditions are relatively favorable. Despite the specific limitations of the case studies, the analysis reveals key insights that lay the groundwork for future research.