Quality control (QC) in lean construction is at the moment in an early stage of development. In fact, QC is nzot yet an integrated part of the overall concept of lean construction. This paper describes the guidelines for a QC system which is coherent with lean construction, and which takes the newest knowledge of lean construction and quality control theory into account. In the TrimByg-QC system [Lean Construction-Quality Control system] a large part of the quality control is executed by the building workers with only limited participation from the site management. When workers are controlling own work their general notion of quality is due to increase, and defects in quality are found and fixed faster than by traditional quality control. In this paper tools and routines for quality control of the site activities "realigning of floor slap panels" and "tamping of concrete elements" are reviewed on the basis of an empirical investigation. The analysis of the data shows that TrimByg-QC has a considerable potential for further testing and development. In connection to such further development six focus areas are identified and described. The future steps should encompass different aspects such as a continued development of the basic tools for worker-based QC and the consideration of legal aspects of building workers' role when controlling their own work.
Quality Control, lean construction, managerial tools.