การประมาณต้นทุนการก่อสร้างของโครงการเคหะชุมชนลาดกระบัง / มยุรี อัศดรวงศ์ไพศาล = An estimation of construction cost of the housing project in Lat Krabang / Mayuree Asadornvongpaisan
One factor among the four necessities of life is housing. The government consequently has shown its keen interest in providing adequate housing for the people. To achieve this goal, the government has given its approval to the National Housing Authority (NHA) to set up the Ladkrabang Housing Community Project, to be included in the state accelerated plan. In order to meet the demand of the public on housing, this project has one important criteria, that is, there will be a cross subsidy among the hire-purchasers while the government will render assistance only on certain necessary aspects, since this project aims to benefit more people than previous projects of the NHA, the types of dwellings to be offered will include that of sites and services so that the costs will be low while the purchasers can expand it as or when they require and are in a position to do it. The author was interested in making a study of this project. The study revealed that calculation of construction cost of the project had been done in three steps:- The first step surveyed the objective groups’ revenue in order to find the affordability rate of payment for each revenue group that would give an estimate of the number and kind of habitats which ought to be built in this project. In B.E. 2521 the Ladkrabang housing Community Project made a survey of the people who would like to live in this project. The areas surveyed were the slums in Klong Toey, companies in the ladkrabang Industrial Estate, factories and industries in the area close to the project; the waiting list which had shown interest in housing to be provided by the NHA was also taken into consideration. The project used the percentage rate of expenditures on housing surveyed by the National Statistics office in B.E. 2518-2519. This percentage rate would help estimating the rate of affordability of payment and the kind of habitat suitable for each revenue group. The second step considered the total cost of the project, which includes the cost of land acquisition, land improvement (flood protection), on-site and off-site infrastructures, provision of community facilities, and construction costs. Also to be included are the expenses of management, the cost of designing and overseeing, interest during construction, some provision for physical contingency and price contingency. To facilitate calculation, these expenses are to be included into total cost by means of co-efficients, the total amount arrived at for the project would then be corporated into a budget in order to ask for a government appropriation. The third step was to allocate the total cost of the project to each kind of the habitats, taking into consideration the cross-subsidy of the various revenue groups among the hirepurchasers. The revenue received from the hirepurchasers and from various government agencies which would be involved in the provision of various facilities must break even with the total cost of the project. Going through the various steps the NHA applied in arriving at the total cost of each type of housing it offered as well as monthly payment for its hirepurchasers, the author has following reservations :- 1) The appropriateness of fixing the cost of management at 2% on other costs. 2) The assumption of interest to be applied only to 2/3 of the period of construction could be very much affected should the period of construction be unduly extended. 3) The state of construction market at the time of the tender for the project would have an effect on the construction cost. The NHA itself seems to have same doubts on the appropriateness of the rate to be charged for management of the Project as it is at present making a study on it. The result of the study will give some indication as to how and what rate should be applied. However, the present study undertaken by the author involved only the estimation of the cost of the project. After the project has been completed, a further study should be undertaken, so that a comparison between the estimated and actual costs could be made which would provide the Government with a basis for decisions involving further beneficial projects.
