Performance and productivity have become buzzwords today, with a major role in many different disciplines. In a society focusing more and more on achievement, the performance and, along with it, the productivity of the individual has become a key factor, not least in the workplace. The requirements people have to satisfy at work are growing, and legally defined working hours are often exceeded due to overtime work. But the crucial question in this context is: Does working more necessarily mean better performance and more productivity? The literature on this topic often defines the limit for productive work with eight hours - any hours worked beyond that result in a deterioration of performance and an increase in costs. The issue of extra and overtime work entailing productivity losses is especially interesting in the context of the construction industry. In addition to the quasi-standard model of 'short week / long week ', tight deadlines often lead to extra time pressure. However, in situations where overtime work is 'ordained' by the management, it can no longer be assumed that the people doing the work can provide full productivity, with claims for compensation of extra cost as a possible result. The purpose of this paper is to provide an aid in situations where compensation for extra cost is claimed as well as an aid for assessing the loss of productivity incurred in different types of work. As well as describing legal frameworks and their differences, the paper looks at productivity from different angles. The key topic of the paper, however, is to analyze loss of productivity in practice. For this purpose, different types of strain found specifically in construction work were analyzed, and the productivity of workers during specific working hours was determined. The evaluation of the results shows a marked loss in productivity.