Quantifying the Impact of Work Environment Factors on Variability of Labour Productivity in Wall Plastering

Variability in labour productivity is a performance inhibitor and a determinant of effective and ineffective projects. It has hampered the intercomparison of construction projects and the accurate forecasting of project duration and cost. This study chose wall plastering activities as a case study. This study aims to quantify the impact of work environment factors on the variability of labour productivity. Data were collected using direct site observations and structured questionnaires. The results revealed that waiting for materials (62.4%), being on the job but not working (52.6%), and work area congestion (52.5%) all had negative effects on labour productivity variance. Other negative factors include rework (51.7%), waiting for tools/equipment (51.1%), waiting for information (47.2%) and weather changes. The overall average daily productivity was 1.268 whr/m2, baseline productivity = 0.993 whr/m2 and variation in daily productivity = 22.08%. The findings identified significant work environment factors and quantified their impacts on labour productivity variability in plastering activity. The results indicate that work environment factors during work in progress significantly impact the variability of labour productivity in plastering work, and ample consideration should be given to its effects.