Abstract:
The objectives of this research were to reduce the expenses incurred and to reduce the time in roof truss installation in building construction work by applying Leans approach to reduce the seven wastages as follows: 1) unnecessary transportation; 2) over inventory; 3) unnecessary movements; 4) waiting time; 5) overproduction; 6) nonproductive activities; and 7) defectives. To ensure high efficient operations, the comparison of cost data and the time between before and after the improvement was made. The analytical results indicated that the cost and the time were decreased. Before the improvement, in the first project, the installation cost was 194.43 Baht per square meter. For the second project; after the improvement focusing on the process of assembly the roof truss to be completed on the ground, the cost of installing roof truss was 89.91 Baht per square meter, 104.52 Baht or 53.76% lower. The working capacity of the first project, was 194.43 square meters per day and the second project was 393.67 square meters per day. The working capacity was 198.99 square meters per day or 49.46% higher. Also, the new capacity was in compliance with the 5 days planned work without having overtime, which really could lower the cost and the time of the projects.
Keywords: Cost reduction, Roof truss installation, Roof truss, Roof truss structure.