From circularity to sustainability: Advancing the whole building circularity indicator with Life Cycle Assessment (WBCI-LCA)

Circular construction is an emerging paradigm aimed at minimizing waste and reducing environmental impacts associated with the construction industry. To support this transition, building circularity indicators have been developed to assess the circularity of construction. While these indicators provide valuable insights into circularity, they lack the capacity to evaluate the environmental impacts of circular interventions. Addressing this gap, this paper presents a novel integration of the Whole Building Circularity Indicator (WBCI) with a comprehensive Cradle-to-Cradle Life Cycle Assessment (C2C-LCA), creating a unified WBCI-LCA framework for assessing circularity and Environmental Sustainability (ES) in circular construction. Applying the framework to a typical Dutch residential building and developing four circular scenarios, this study demonstrates how WBCI and C2C-LCA approaches can be effectively combined to examine the complex trade-offs between circularity and ES. The findings reveal that while increased circularity (from 0.309 to 0.488 in developed scenarios) reduces environmental impacts in most categories, it may also shift burdens across categories. For instance, biobased materials like CLT reduce global warming potential but increase eutrophication potential depending on the end-of-life scenario. This integrated approach demonstrates that WBCI and C2C-LCA effectively complement each other: WBCI captures essential circularity aspects like material circulation and component disassembly, while C2C-LCA provides insights into the environmental impacts of manufacturing, recycling, and transportation processes. These findings advance the literature on building circularity indicators by extending their applicability to C2C-LCA and contribute to the broader discourse on sustainability and circularity by providing empirical evidence on their interrelationship.