A stratified building carbon emission model from a dynamic life cycle perspective

To address the imperative of decarbonization in the building industry, this study overcomes the limitations of conventional static Life Cycle Assessment, which overlooks the cumulative carbon impact of dynamic retrofits. Based on Shearing Layers theory, we propose a four-layer Stratified Framework encompassing Skeleton, Space & Partition, Equipment, and Interaction. This study establishes a matrix-based model to quantify emissions across the material production, construction, and operational stages. The Modularity Coefficient is introduced as a key parameter to characterize generalized construction carbon emissions, while the structural robustness of the model is systematically evaluated. Findings reveal that in the material production stage, the Space & Partition Layer contributes significantly due to its substantial physical volume and periodic replacement cycles. In the construction stage, associated losses caused by construction methods constitute the core variable of construction carbon emissions. During the operational stage, the Interaction Layer facilitates a cross-layer synergistic emission reduction pathway via intelligent optimization. This systematic methodology provides a theoretical foundation for life-cycle carbon accounting and provides strategic support for optimizing low-carbon retrofitting and sustainable renewal technologies for existing building stocks.