Evaluating the Circularity and Carbon Benefits of End-of-Life Timber Structures: An Integrated BIM-LCA Approach

As the construction industry seeks to reduce carbon emissions, timber has emerged as a key material due to its capacity for biogenic carbon storage and end-of-life (EoL) reuse. However, assessing the practical circularity potential of timber structures remains challenging. This is largely because recovered components suffer geometric and material losses at their connection points. This study evaluates the EoL reuse and recycling potential of a multi-storey timber building by combining Building Information Modelling (BIM) with Life Cycle Assessment (LCA). A digital model was used to quantify structural elements (beams, columns, and walls), explicitly accounting for material losses at connections to calculate the net recoverable timber. The recovered material (837.39 m3) was assigned to various cascading use scenarios based on material strength: structural reuse, non-structural reuse, engineered wood production, and energy recovery. To align with ISO 14044 principles, a functional equivalence factor (Q-factor) was applied to measure the environmental benefits of substituting new materials. Results indicate an overall material loss of 16.62% due to connections. Among the evaluated EoL pathways, structural reuse yielded the greatest net carbon benefit (−128.7 tCO2e), significantly outperforming lower-value alternatives such as energy recovery (−29.3 tCO2e). Additionally, a Design for Disassembly (DfD) sensitivity analysis showed that reducing connection losses by 50% could increase net global warming potential (GWP) savings by up to 19.7%. In conclusion, connection design is a critical factor in enabling timber circularity. Furthermore, combining BIM material tracking with LCA methods offers a practical approach to quantifying the long-term carbon benefits of timber reuse strategies.