The impetus towards efficiency in the AECO (Architecture, Engineering, Construction & Operations) sector is driving the implementation of Lean practices. BIM technologies and BIM processes provide methods by which this can be achieved. Major clients of building services contractors have begun to mandate the use of BIM and some are using BIM preparedness/experience as pre-tender qualification criteria. In this case study, an initial review has been conducted of the achievements of a major Irish M&E contractor in implementing BIM. The firm purpose-built a facility for the off-site manufacture of building services components. The operations of the plant are efficient and qualityassured through the use of an appropriately skilled workforce at all stages of manufacture, and tracking software that has developed as the knowledge of the contractor grew. Standardised processes have been developed which have resulted in greater efficiencies and lower costs for the contractor as a result of fewer requirements for onsite modifications (such as those caused by clashes), less waste, and greater flexibility. Despite some initial objections, the employees of the company are now more satisfied with their working conditions and are, as a result, more productive. Through investment in BIM-based, Lean processes, the contractor can now better compete when tenerding for large-scale projects in Ireland and worldwide, including the rapidly-increasing number where BIM experience and preparedness is mandated.