Abstract:
Nowadays, housing developers can choose to build their own factory or select a supplier for a pre-fabricated component to be used in their projects. The objective of this comparative study is to look into the basic expenses between building a factory and selecting suppliers from which to buy pre-fabricated components in order to minimize unexpected expenditures that might occur in developing housing construction project. Place and Park housing project was selected to be analyzed by comparing between using pre-fabricated materials and on-site fabricated load-bearing wall component by studying a house of 180 square meters in this report. The house was constructed using a method very much like the conventional construction method. The study found that if a house developer builds a factory, the cost of land, equipment, machinery, services, and labors will be affected significantly. On the other hand, if a house developer chooses to buy materials from a component supplier, such costs will not occur, only the cost of modification to the industrialized building system, and the construction cost. The result of an investment cost analysis revealed that if a house developer invests in the construction of a factory, primary costs of land, building materials, machinery, management, plan adjustment and labor will be high at the start. Moreover, approximately 38 units of houses (6,840 square meter) must be constructed to bread-even at an average investment and construction cost of 5,310.33 baht per square meter. If the developer buys a pre-fabricated component from a supplier, or hires a contractor to build an on-site factory, the average cost will be 6,897-8,700 baht per square meter. And if the developer uses the conventional method of construction the average cost will be 6,965 baht per square meter. In terms of the length of construction time, it will take 94 days to build one house if the developer chooses to build an on-site temporary factory to manufacture the needed components, the construction of which will take another month to complete. From the study, it can be concluded that if a house developer chooses to build a factory with fewer than 38 houses (6,840 square meters) in the project, the investment cost will be significantly affected. To break-even, a house developer should buy pre-fabricated components from suppliers. For a project with over 38 housed, on the other hand, building an on-site factory will be more effective in terms of investment cost, construction time, and style However, this comparative study is merely a primary comparison. The comparison of prices in this report used prices as of September 1999.