Assessing the Effects of Contract Variations on Building Construction Delivery

Contract variations are a common phenomenon in building projects, often leading to time overruns, cost escalations, and dissatisfaction among stakeholders. Despite numerous studies on variation orders, there is limited empirical evidence on their effects on building project delivery within the Nigerian context. This study assessed the effects of contract variations on building construction delivery, with a view to identifying critical causative factors, their impacts on performance, and possible mitigation strategies. A quantitative research approach was adopted using a structured questionnaire administered to 100 construction professionals comprising clients, consultants, and contractors, with a response rate of 92%. Descriptive and inferential analyses were conducted using Frequency, Mean Item Score (MIS), and Spearman’s rho correlation. The findings revealed that the most significant factors responsible for contract variations were consultants’ lack of experience, design complexity, and additional client instructions (MIS = 5.00 each). The major effects identified included time overruns and end-user dissatisfaction (MIS = 5.00), while loss of efficiency due to work interruption (MIS = 4.84) was the most critical impact on project performance. A strong positive correlation was observed between consultant experience and time overrun, indicating a direct relationship between technical expertise and project timelines. The study further established that loss of profit (MIS = 4.26) and reduced organisational performance were major consequences at the organisational level. Key mitigation strategies include effective communication, proper site investigation, comprehensive design documentation, and interdisciplinary collaboration. The study concludes that effective management of contract variations can significantly enhance project delivery outcomes, cost performance, and client satisfaction in building projects.