There have been several knowledge-based systems for statutory building regulations during the last decade, such as Fenves et al's systems using the SASE model, Stone and Wilcox's system using a rule-based approach, and Waard's system using Cornick et al;'s model-based approach. However, they take into account only one side of building regulations, considering them only in the context of design systems and ignoring the existence of case histories. Building regulations are also part of a legal system and have characteristics of law. In this paper, we propose a Knowledge-Intensive Case-based reasoning System which can be used for the retrieval and maintenance of building regulations and case histories. First, we propose a unified knowledge representation scheme for both statutory building regulations and case histories. Second, we describe the retrieval of regulations information, which uses the notion of implied similarity as well as structural mapping. Finally, we describe knowledge acquisition from case histories, which is guided by knowledge gained from statutory regulations and case histories.