This study assesses 12 types of project overhead costs, 6 methods of allocation and 15
factors which affect project overhead costs in South-South of Nigeria. The objective is to compare
small and medium contractors’ perception of the methods of allocation, factors affecting project
overhead costs and the effect of the types of project overhead costs on cost, time and quality of the
projects. Data were obtained through 501 structured questionnaires administered to small and
medium contractors and analysed using mean item score, and Mann-Whitney U test. The
results reveal that contractors perceive that supervision costs, cost of rework, equipment
management costs, general field expenses, and temporary works costs were prominent
overheads affecting cost, time, and quality performance of projects. There is no difference in the
contractors’ perceptions of issues affecting overhead costs. It is recommended that contractors
should give adequate priority to significant project overheads and their influencing factors.