Comparative Analysis of Construction Waste: Robotic Vs. Manual Offsite Assembly

Construction waste (CW) is a significant environmental concern that started to shape the future of the construction industry. Offsite construction (OSC) is one key approach widely praised for its capability to reduce CW due to its controlled environment where lean and technology principles can be applied. Despite the growing research confirming OSC capability to promote productivity and reduce lead times, evidence on material efficiency is highly limited. Hence, this study aims to fill this gap in the literature by conducting a comparative case study to investigate CW generation in OSC. Two timber frame panelised construction factories were approached with OSB assembly stations chosen to investigate how, how much and why CW is generated and whether lean and technology uptake are supporting CW reduction. While Factory A adopted a manual station to assemble the OSB layer, Factory B adopted a fully automated robotic station. The results indicate that the robotic station generated significant offcuts, accounting for 27% of the total OSB usage, compared to 16% generated by the manual station. The application of lean and technology practices is found to primarily focus on workflow, time, and cost, with limited consideration to material efficiency.