Comparative study of conventional and emerging façade systems: Pathways to reducing embodied carbon and enhancing circularity in buildings

Façade systems play a critical role in building environmental performance, contributing substantially to embodied carbon due to their material intensity, exposure-driven replacement cycles, and complex assemblies. As operational energy demand decreases under increasingly stringent energy regulations, embodied impacts associated with facades are becoming a dominant component of whole-life building emissions. Conventional façade systems typically follow linear end-of-life pathways, resulting in limited material recovery and significant waste generation. Circular economy (CE) principles offer a pathway to address these challenges through durability, design for disassembly, reuse, and high-value recycling; however, comparative assessments integrating environmental performance and circularity across façade typologies remain limited. This study evaluates the whole-life environmental and circularity performance of six façade systems—three conventional and three emerging—within the contemporary Australian construction context, using a combined Life Cycle Assessment (LCA), with global warming potential (GWP) as the primary environmental indicator, and a circularity assessment. The analysis covers all life-cycle stages, enabling consistent comparison across contrasting material compositions and assembly strategies. The results reveal clear trade-offs between embodied carbon and circularity. Conventional systems such as Concrete Masonry Units (CMU) exhibited 446 kgCO₂e per façade module, whereas Rammed Earth achieved 285 kgCO₂e, and Hempcrete–CLT reached net negative emissions of −268 kgCO₂e when accounting for biogenic carbon storage. Circularity scores ranged from 21 to 28% for conventional systems to 35–77% for bio-based alternatives, with Rammed Earth achieving the highest circularity (77%). Dry-assembled systems such as Brick Slip Timber Frame further improved circularity performance (39%) through mechanically reversible connections. Overall, the findings highlight that façade circularity is shaped by system-level design decisions rather than material choice alone, underscoring the importance of integrating environmental and circularity considerations during early façade design stages.