||"For more than 40 years, computers have been associated with the delivery of construction activities. From large mainframe machines, construction applications have migrated to the full realm of processors - embedded to palmtops to desktops - and to different types of environments, as much on-site in space or underground as in the office. The matrix-based stiffness method on punched cards in batch mode has long ago given way to graphics-based interactive user-interfaces on the Web that give access to a myriad of applications that can support most aspects of the work of construction professionals. In view of such progress, what is left in terms of computer-mediated support for construction that is not already available?The short answer is integration. Much of the construction industry in the world today, certainly in North America, is still characterized by fragmentation. Even though computer support for construction is available in a multitude of ways, effective integration across actors, over the entire life-cycle and covering all components that compose building projects is still in its infancy. At the present time, commercial integrated solutions are more prevalent at the detailed design stage in the form of ""design suites"" of applications for drafting, structures, HVAC, estimating etc. The authors have developed, over many years, a number of integrated building design prototypes at the preliminary stage by means of novel computing techniques derived from AI and product/process modelling. The purpose of this presentation is to push the exploration further upstream at the conceptual design stage, when decisions involving only few individuals have the greatest impact on the life-cycle performance of the building delivery process. On the basis of an extensive literature review, analysis of current design environments and protocol analysis of designers actually engaged in such work, we will identify key concepts and activities that are essential at the conceptual design stage, with the view to propose and implement a computer-based prototype capable of providing effective support."