What are the Main Causes of Discontinuous Work?

Discontinuous work in construction refers to periods without resource or work continuity, leaving workers without designated locations to perform their tasks. Studies show in many activities idle durations are a significant portion of total work. Caused by poor production system design in projects, discontinuous work is a major cause of low trade productivity. This paper aims to identify factors affecting discontinuous work and quantify their impact. 346 datapoints (including 46 superstructure crews across 75 building levels in 10 multistorey buildings in London) were analysed using correlation and regression techniques. Data included crew size, batch size, activity type, work start and end dates. Results showed that reducing the batch size by increasing slab concrete pours per level minimised discontinuities by ensuring more available work locations. Synchronising the production rates of successive crews also reduced discontinuities by limiting idle time for faster crews. Surprisingly, although often considered a cause of discontinuities, out-of-sequence work had no statistically significant relationship with discontinuities. Possibly due to the constraints of superstructure work limiting the out-of-sequence work. Additionally, offsite construction methods exhibited greater variability in discontinuities compared to in-situ methods, likely due to clashes between in-situ activities happening at a different rate of work to offsite activities.