Reducing plan variations in delivering sustainable building projects

• Lower productivity found in activities with relation to sustainable deliverables.
• Critical areas related to poor production performance were found.
• The implementation of LPS resulted in significant reduction of plan variations.
• Reduction of plan variations was found related to increments in productivity.

In line with promoting the mission of sustainable development, the sustainable building practice has been increasingly adopted in recent years. However, the process of delivering a high performance sustainable building has led to a more complex construction practice through the increment of specialized processes. Such complexities have affected construction sequencing and timing, leading to workflow variability and excess in the estimated construction time and cost. In this study reducing plan variations is considered a key improvement in the delivery process of sustainable building projects. This research used the Last Planner System (LPS) to develop a more reliable production planning process to reduce plan variations. A case study was conducted focusing on the measurement of production performance of activities and the reasons for non-completion before and after LPS implementation. The critical areas relating to poor production performance of activities were identified. Results demonstrated differences in production performance and causes of plan variations between activities in relation to and with no relation to sustainable deliverables. While the difference in the production performance is not considerable, the difference in the causes of variability is significant. The implementation of LPS resulted in a significant reduction of plan variations. As variability decreased, production performance of activities increased. The findings from this study contribute to alternative methods for an effective production planning process for sustainable building projects.