This PhD thesis explains the development stages of an expert system for the evaluation and selection of building elements during the early stages of architectural design. This expert system is called BES. It is produced after two prototypes were established. Testing of BES is made on professional architects who are from both academia and the practical construction market of Northern Cyprus. BES is intended to be used by experienced and inexperienced architects.The model includes selection of all kinds of main building elements that are available like retaining walls,foundations, external walls, internal walls, floors, external stairs, internal stairs, roofs, external chimneys, internal chimneys, windows and external doors and internal doors and their sub-type building elements. The selection is achieved via SMART Methodology depending on the performance requirements and an expert system shell Exsys Corvid version 1.2.14 is used to structure the expert system.