Analysis of Labour Productivity Factors on Highrise Building Projects in Lagos Island

Labour productivity is a critical determinant of construction cost and programme performance, particularly on high-rise projects where operational complexity and coordination demands are amplified. This study analyses the factors affecting labour productivity on high-rise building projects on Lagos Island, where commercial and residential tower development has accelerated in recent years. A quantitative survey design was adopted, with 90 site-based professionals including site managers, quantity surveyors, and labour supervisors forming the sample. Structured questionnaires were administered and data analysed using relative importance index and factor analysis. Findings identify material supply disruptions, poor site access logistics, inadequate supervision, and harsh weather conditions as the leading productivity inhibitors on Lagos Island high-rise sites. The study further finds that labour disputes linked to delayed wage payments reduce site productivity by an estimated 18% per incident. Conversely, effective gang organisation, provision of adequate welfare facilities, and use of tower cranes significantly improved measured productivity outputs. Recommendations include systematic labour productivity monitoring using earned value metrics, structured incentive pay schemes tied to output targets, and improved logistics planning for material deliveries in restricted urban sites. Construction firms are encouraged to adopt building information modelling platforms to optimise workforce scheduling. This research contributes practical insights into labour cost management for urban high-rise construction in the South West geopolitical zone. Keywords: labour productivity, high-rise buildings, Lagos Island, construction management, cost factors