Analysis of Building Construction Project Management Using Lean Construction Approach to Determine Cost and Time Waste in the Construction Project of Pondok Pesantren Syifaul Qulub Surabaya

This research investigates cost waste in detailed engineering design for the Syifaul Qulub Surabaya Islamic Boarding School construction project, aiming for on-time, on-budget completion. Utilizing a Lean Construction approach, the study analyzes waste reduction in this densely populated, limited-access urban environment. Primary data from questionnaires were processed to weigh waste in each activity, followed by value stream analysis tools, including Process Activity Mapping, to identify Value-Added (VA) and Non-Value-Added (NVA) activities. The findings revealed that waiting was the primary cause of waste, contributing to 41.8% of critical waste and a 33-day project delay. Root causes included material procurement issues, transportation challenges, and equipment problems. Waste accounted for 21% of all project jobs, categorized as Unnecessary Movement (13.7%), Transportation (12.2%), Material Defects (11%), Storage (10.9%), and Overproduction (6.8%). By addressing these wastes through targeted Lean interventions, the research suggests a potential project acceleration of approximately 16.5% (33 days) and a cost reduction of 5-10% by optimizing resource use and minimizing material waste. These results demonstrate the practical benefits of Lean Construction in mitigating inefficiencies and delays in challenging urban builds.