This paper presents a life cycle assessment (LCA) methodology for evaluating the environmental impacts of reuse in building projects and apply it to a case study in Switzerland with 11% of reused components in its total mass. The results show that the life cycle GHG emissions on the construction domain that includes modules A1 to A4, B4, and C1-C4, are 487 kg CO2-eq./m2. In the other hand, the indirect effect of reuse lead to avoided GHG emissions of 76 kg CO2-eq./m2. At the level of a product's supply chain, the analysis demonstrates a significant reduction in the embodied impacts of the reused components compared to newly manufactured ones. The potential benefits from avoided manufacturing and waste management depend on the type of material that is reused.