The fact that ontologies are considered shareable and reusable components has always been claimed as one of their main advantages. While reusing ontologies is promised to reduce time and resources invested during ontology development, the experience shows that reusing ontologies also involves a costly effort. In this work, we first analyse how ontologies representing the building domain currently reuse each other. Finally, we detect existing Web Ontology Language (OWL) modelling patterns in the ontologies analysed and generate a graphical pattern library to facilitate reuse of the observed patterns.