The research work presented here is concerned with the development of a knowledge-based system to assist novice designers in conceptual design. Conceptual design is the first stage in the design of buildings during which a number of structural schemes are formulated and accessed. It is a task that requires experience, knowledge and creativity as much is unknown and ill-defined. It involves activities and decisions that are highly judgemental and heuristic in nature. An approach is presented here for developing a knowledge-based expert system to assist and educate young designers in this task. A system currently under development is discussed. The system is being developed within KappaPC, the chosen expert system toolkit, using object-oriented methodology.