The contribution deals, describes and analyzes the fundamental connection between defects and the design of a building. Approximately half of the faults occur in building objects due to incorrect or faulty design activities. The non-conceptual approach to managing building preparation and insufficient and unqualified project design control poses problems with building use and increases the cost of maintenance. Improving engineering design and a comprehensive approach to project preparation and preparation is a way to increase the quality of design work. In his contribution, the author relies on quality management systems and their implementation in design offices and companies. At the same time, the term is a complex project, which would be a control tool for the quality of projection work.