Integrating three pillars of sustainability for evaluating the modular construction building

Purpose – The purpose of this study is to evaluate the sustainability performance of modular construction from a life cycle perspective. So far, the sustainability performance of modular buildings has been explored from a life cycle viewpoint. There is no comprehensive study showing which material is the best choice for modular construction considering all three sustainable pillars. Therefore, a life cycle sustainability performance framework, including the three-pillar evaluation framework, was developed for different modular buildings. The materials are concrete, steel and timber constructed as a modular construction method. Design/methodology/approach – Transitioning the built environment to a circular economy is vital to achieving sustainability goals. Modular construction is perceived as the future of the construction industry, and in combination with objective sustainability, it is still in the evaluation phase. A life cycle sustainability assessment, which includes life cycle assessment, life cycle cost and social life cycle assessment, has been selected to evaluate alternative materials for constructing a case study building using modular strategies. Subsequently, the multi-criteria decision-making (MCDM) method was used to compute the outranking scores for each modular component. Findings – The calculated embodied impacts and global warming potential (GWP) showed that material production is the most critical phase (65%–88% of embodied energy and 64%–86% of GWP). The result of embodied energy and GWP shows timber as an ideal choice. Timber modular has a 21% and 11% lower GWP than concrete and steel, respectively. The timber structure also has 19% and 13% lower embodied energy than concrete and steel. However, the result of the economic analysis revealed that concrete is the most economical choice. The cost calculations indicate that concrete exhibits a lower total cost by 4% compared to timber and 11% higher than steel structures. However, the social assessment suggests that steel emerges as the optimal material when contrasted with timber and concrete. Consequently, determining the best single material for constructing modular buildings becomes challenging. To address this, the MCDM technique is used to identify the optimal choice. Through MCDM analysis, steel demonstrates the best overall performance. Originality/value – This research is valuable for construction professionals as it gives a deliberate framework for modular buildings' life cycle sustainability performance and assists with sustainable construction materials.