Architects need to update design requirements whenever user information changes during project development. However, they often do so manually because current theories do not effectively capture the rationale behind the generation of requirements, which is often related to the activities of building users. In this paper, we formalized the relationship between design requirements and the user information in support of automated updating of the requirements. We then developed an automated requirements updating method comprising three phases: updating of user information, updating of the requirements for each space type, and adjustment of the numbers of space types to satisfy target utilization. We validated our method by comparing, for the same case example, the performance of a prototype system with that of experienced architects with respect to updating design requirements according to user information changes. Deployment of this method would allow architects to update design requirements quickly and accurately during project development. (C) 2014 Elsevier B.V. All rights reserved.