Previous approaches to decision support for project planning using rule‐based expert systems techniques have failed to make an impact in practice. This is primarily because of the complexity and large‐scale nature of construction information, and problems with expert systems including: knowledge acquisition; rule‐based knowledge representation; information storage (or memory); learning; and robustness. Case‐based reasoning is one area of current research which may hold the key to overcoming a number of these problems. In the present paper, previous related case‐based reasoning work is examined. The key factors which influence the formulation of construction project plans are identified. This knowledge is used to develop a conceptual framework within which previous planning experiences can be captured and reused in new situations as a means of providing system decision support in construction planning and control. A prototype system, CBRidge, developed to test and demonstrate the concepts within the framework is presented. The results are very encouraging and provide a sound basis for the further development of case‐based reasoning for construction planning in practice.