The industry is nowadays confronted with large-scale monolithic and inflexible object-oriented software. Because of their high business value, these legacy systems must be reengineered. One of the important issues in reengineering is the detection and location of design flaws, which prevent an efficient maintenance and further development of the system. This work presents a novel metrics-based approach for detecting such design problems. The approach is based on the Detection Strategy concept, which is a higher-level mechanism for interpreting measurement results, defined by the author. After defining and explaining the mechanism itself, the work introduces an important suite of detection strategies for the identification of different well-known design flaws found in the literature, but also for problems rarely mentioned. The last part of the work introduces a new type of quality model, called Factor-Strategy.