The problem of georeferencing building information modelling (BIM) models is complex and in need of a comprehensive solution. We focus on the open BIM data format Industry Foundation Classes (IFC) and its georeferencing specification. The requirements voiced by the domain experts during recent years have been collected and analysed. While IFC already covers some of the concepts, an extension to the IFC schema was proposed which handles theinadequacies. The proposal composes of several new entities, which support geographic coordinate reference systems (CRSs), a well-known text (WKT) representation of a CRS and a rigid transformation of BIM geometries within chosen CRS. The improvements assure much-needed semantically clear definitions of the georeferencing concept within the IFC datamodel. As such, the interpretation of IFC data content is unambiguous for stakeholders, software implementers, and end-users.