Abstract:
Project's overhead cost, which is vital to the project success, is one of the indirect costs of construction projects.
This study investigated the overhead cost of construction in Thailand. Questionnaire that was developed based
on the information from expert interview was sent to verious construction projects. Fifty-one questionnaires
were rececived and analyzed. It is found that the average overhead cost 14.76 percent of construction value and
most of the contractors in Thailand nomally based the overhead cost by using the percentage of project value. t-test
at 95 percent confidence level was used to compare the difference of the estimation of the overhead cost between
differences projects attributes. It was found that there are no differences in overhead cost when project's attributes
were different. Thus, this indicates that most of project overhead cost have been managed without proper planning,
controlling and budgeting. In this research, various project overhead cost construction project have been compiled,
analyzen, and categorized into 8 groups. The study shows that the largest proportion of the project overhead cost falls
into the category of site office preparation, temporary structure and utilities system. In addition, the most important group
of the project overhead cost is the construction support.