Abstract
PurposeIn the construction industry, an under researched area of study is how main contractor (MC) sub-contract design responsibilities to sub-contractor (SC). This lack of knowledge is particularly serious in the context of delivery methods such as design and construct where design responsibilities are pushed down the supply chain. In this study, it is aimed to explore which level of design responsibility MCs sub-contract to SCs, for what reasons, and what the impact of sub-contracting decisions is on projects.Design/methodology/approachA qualitative in-depth multiple case study was conducted. Six sub-contracting cases were examined in two civil engineering projects. In each project, the MCs sub-contracted pre-fabricated beams, reinforcement and railing to SCs. Data collection included document analysis and interviews. A within-case and cross-case analysis was conducted to examine emerging empirical patterns. These patterns were used to elaborate theory and develop propositions.FindingsMCs sub-contracted design responsibilities to SCs as suggested by literature. However, despite that sub-contracting was in keeping with literature, several problems were reported in the cases where MCs involved SCs no earlier than in the construction stage. This is not to be expected according to theory.Originality/valueThis study adds value to the sub-contracting field as it provides new insights in relationships between the level of design responsibilities sub-contracted and the impact of that on projects. The study also revealed new factors such as building information modelling (BIM) interoperability that should get more attention in sub-contracting.