Evaluating Circularity in Life Cycle Assessment based on the Case Study Re-Use Ziegelwand

Abstract

The construction sector is a major driver of global material consumption and greenhouse gas emissions, making circular construction strategies increasingly important. Building life cycle assessment (LCA) according to EN 15978 provides a standardized framework for evaluating environmental performance, but circular benefits arising outside the spatial or temporal boundary of an assessed project are often insufficiently captured. In particular, avoided burdens enabled by reuse-oriented design, selective demolition, or component reuse across multiple building life cycles remain poorly visible in conventional assessments. This paper proposes a multi life cycle scenario of Module D that transparently attributes such avoided burdens to the projects that enable them, without modifying existing system boundaries or introducing consequential modeling. The approach is demonstrated using a case study of reusable exterior wall systems applied to supermarket buildings over multiple life cycles. The results show that reuse-related environmental benefits accumulate over successive building cycles and can be meaningfully attributed within a single-life-cycle assessment when boundary effects are made explicit. The proposed interpretation improves the transparency and comparability of circular construction strategies within the existing EN 15978 framework.