Material Waste Analysis Using Lean Construction In the Project of Gedung Hunian Lembaga Pemasyarakatan Narkotika

Material waste poses cost in the construction project management process. This research aims to determine the quantity of high-cost material waste and pinpoint the primary causes of waste in the Gedung Hunian Lembaga Pemasyarakatan Narkotika construction project. Employing a lean construction approach, data were analyzing using the IBM SPSS 26 application. Material waste levels were calculated by comparing the waste volume and the total installed material, while the Borda method was utilized to rank the most influential waste indicators. The results analysis identified three high-cost materials: threaded rebar, K-300 ready-mix concrete, and plain rebar. Specifically, the percentage of material waste level for threaded rebar were 1% (D19), 11% (D16), 3% (D13), 5% (D10); K-300 ready mix concrete was 3%; and for plain rebar were 5% (Ø12), 1% (Ø10), and 0% (Ø8). Overproduction variable, characterized by an indicator of overuse of materials that exceed the needs, emerged as the main causative waste factor, weighing 0.45. These findings provide actionable insights for minimizing material waste and improving cost efficiency in construction projects.