PurposeThe “big room” concept and lean philosophy have become increasingly popular in the construction industry. Visual control is a central part of lean philosophy and the big room concept; its aim is to improve information flow, joint problem-solving and real-time decision-making. Visual control facilitates effective project management by providing information on what work is performed and why, customer requirements, deadlines, work status and potential problems. This study aims to explore how visualisation supports project management and control in a big room and the factors that facilitate good visual control.Design/methodology/approachThis research is based on the case study method, and the objective is to elaborate the current understanding of factors that affect visual control. The study includes a literature review and an empirical study of a large construction project.FindingsThe results indicate that many factors facilitate visual control. Despite the importance of facilities and tools, communication and teamwork are identified as the key factors. On a broader level, the results indicate a need for a holistic approach in developing visual management strategies and practices in the construction industry and in complex projects in particular.Research limitations/implicationsA single case may not be able to offer a generalised picture of this complex topic. However, the study provides novel insights for practitioners and researchers interested in the development of visual control and big rooms. Future research topics are also proposed.Originality/valueWhile previous studies have identified many elements of successful big room implementation – including integration and early involvement, information sharing, tools and facilities – this study focusses specifically on the factors that facilitate visual control.