The construction industry, a major economic driver, is also a significant environmental polluter. Prefabrication emerges as a sustainable alternative due to its reduced resource consumption, waste generation, and energy use. This study proposes a MIVES-based model to assess the sustainability of precast concrete buildings compared to traditional concrete, considering environmental, economic, and social factors. A five-story commercial building in Reggio Calabria, Italy, was used as a case study. Two construction methods were compared: traditional cast-in-place reinforced concrete and a low-damage precast concrete alternative. Criteria and indicators were defined for each sustainability pillar, weighting them based on importance. Value functions converted indicator values into comparable scores. By combining these scores, a final sustainability index was calculated for each building. Precast concrete showed potential benefits in construction time, reduced emissions, and less construction disturbance. A sensitivity analysis confirmed the results. While this study highlights the potential advantages of precast construction over traditional methods, it is crucial to acknowledge the context-specific nature of the findings. The model's applicability is limited by factors such as building materials, structural conditions, and regional regulations. However, its adaptable framework can be tailored to evaluate diverse construction methods in different settings. By carefully adjusting parameters and functions, the model can offer valuable insights into the relative sustainability of various construction approaches.