9.2. Extra costs of projects The research reveals that 77% of the projects faced financial problems due to the use of unskilled work forces. In contrast, 23% of the projects, which entrusted their work to skilled labour, had less additional costs. It shows that skilled labour plays an important role in decreasing extra expenses in construction projects. Referring to the respondents, most of the projects additional costs related to rework activities due to inadequate skilled work forces.