Analysis of Time Reduction Using The Lean Construction Method in The Construction Project of The Syifaul Qulub Islamic Boarding School in Surabaya

The focus of this research is to reduce the cost and time waste associated with detailed engineering design in the hope that the project can run as planned and on time so that the actual costs can be accurately understood. The purpose of this study is to analyze the reduction of time waste in the construction project of the Syifaul Qulub Islamic Boarding School Surabaya with a lean construction approach. This study uses the Lean Construction approach which processes raw data through a questionnaire to determine the percentage of waste weight in each activity. The analysis was carried out with value stream analysis tools, identification of VA and NVA activities, process activity mapping analysis, root cause analysis, analysis using Pareto diagrams and fish bone diagrams to identify wasteful solutions. The main cause of waste in this project is the waiting factor which reaches 41.8% in the analysis of the weight of critical waste. This resulted in the project being delayed for 33 days. The root causes of waste in the construction project of the Syifaul Qulub Islamic Boarding School Surabaya are delays in the arrival of materials and machines, difficulties in handling materials, lost equipment, damaged equipment, untidy work techniques, and workers who take breaks during working hours. The waste ratio for a total of 35 jobs is 21%. Types of waste include waiting 41.8%, unnecessary movement 13.7%, transportation 12.2%, material defects 11%, storage 10.9%, overproduction 6.8% and work processes that do not comply with SOPs 3.6%.