Delay in building construction project is a universal phenomenon that is not peculiar to Osun alone. In fact, all countries of the world are faced with this global issue. These delays are usually considered as costly to all parties concerned in the projects and very often results in total abandonment thereby slowing down the growth of the construction sector. The purpose of this study was to assess the causative factors of delays and their effects on building construction projects in Osun. A total of forty two (42) project delay attributes and seventeen (17) effect attributes were identified through detailed literature review. Questionnaire survey were conducted across stakeholders that included among others; consultants, contractors and clients cutting across the building professionals namely; Architects, Builders, Quantity Surveyors, Estate Surveyors and Engineers to gather their views on causes of delay in delivery of projects. The research categorized the causes of delay under four main groups of client related, consultant related, contractor related and delay caused by incidental factors and their effects assessed using relative importance index (RII) as a basis for analysis. The RII for all delay factors and group of categories was computed so as to rank the factors. A total of 260 questionnaires were distributed among the respondents from different building construction firm in Osun state. Out of 260 questionnaires distributed, 234 valid questionnaires were retrieved back from the respondents, representing a response rate of (90.0%). The validation of information in this study yielded a Cronbach’s alpha of 0.891. The most significant factors of construction delays were identified as: cash flow problem (delay payment) with (RII=0.89), incomplete drawings (RII=0.84), improper planning and scheduling problem (RII= 0.91), financial incapability (RII = 0.89) and force majeure (Acts of God) with (RII = 0.81). The study revealed that overall, contractor-caused delays ranked highest with (RII=0.91) and was attributed to improper planning and scheduling problem, followed by financial incapability (RII = 0.89), while client-caused delay attributed to cash flow problem (delay payment) (RII=0.89) was observed as the second most common cause of delay in building construction project in Osun state. Furthermore, the study revealed increase in final cost of project (RII = 0.88) and extension of time on project (RII = 0.80), as the top two (2) effects of delays in building construction project in Osun state, while cash flow (RII = 0.52) had the least effect. It is therefore believed that identification of the causes of potential delay factors that are likely to affect the timely delivery of projects can help to avoid extra costs through claims and disputes that arise among parties when delays are experienced.
Keywords: Causative factors, Construction Projects, Construction delays, Effects of delay, Nigeria, Osun State, RII