A lean approach to capacity management in construction

Lean construction has not been universally adopted in the UK construction industry and has had little application in heavy construction although there has been a greater uptake in the housing sector. The research has identified a number of factors, both at construction site and corporate level, which have prevented the adoption of lean principles. Firstly, the segregation of buying and construction management departments means that buyers consider only the bottom line cost of materials rather than the complete cost to a project. This results in buyers ordering materials in the maximum possible quantities to attract the largest bulk discounts without considering the associated costs. Secondly, construction site staffs have a deep-rooted fear of running out of materials and hence prefer to hold large stocks of material on site. Thirdly, high variability in output occurs in construction and where adoption of lean has been attempted, schedules have not been met and there has been an increase in defective work. Finally, the concepts of, cycle time and work scheduling are not properly understood at site level. The research initially produced a scheduling calculation model based on four methods taken from operational research: least cost; North West corner; Vogel's approximation and longest required time. The model was trialled on a construction site on the University campus. The results showed that when activities were dominated by machines the model performed well but when activities were dominated by people the variability in output made the schedules predicted by the model unworkable.