Large amounts of information are being accumulated nowadays due to the use of information systems in construction firms. Among them, the reusable legacy information can be referred to as 'information resources' and two approaches have been adopted to utilize them, i.e. to utilize them by using general-purpose software such as Microsoft Office, or by using specialized software such as BI (Business Intelligence) software. Identifying and representing the information resources is the essential step in both approaches. This research identified decision activities and information resource items through literature reviews and two expert workshops: an evaluation workshop and a verification workshop. The reusability of information resource items was evaluated in the evaluation workshop and validated in the verification workshop. A way to represent information resources by using IFC was formulated and an extension of IFC was developed and validated based on the analysis of information resources. This research will benefit construction firms in utilizing the information resources more effectively and efficiently to support decision-making in their project and enterprise management.