The use of Expert Systems in construction is not new. These systems have been developed either as stand alone modules or integrated with commercially available algorithmic software systems. This paper describes the development of a PC-based expert system for the assessment of the constractability of a design detail. Knowledge for this particular domain was gained from design engineers, architects, and field practitioners such as site and planning engineers. The development of the appropriate knowledge acquisition and integration techniques are covered. The system is tested with practitioners and novices and the concept of consultation is validated.