This paper deals with analysing and evaluating design suitability for a given environment. A design is deemed to “fit” into the environment in which it is planned to be built if it follows the same style and shows sufficient “closeness” to other buildings in the area. The knowledge about the designed building is encoded in the form of a labelled graph. To test the conformity of the design with a given style an ontology-based graph approach is proposed, while to calculate the degree of similarity of the design to other designs graph mining methods are used. The proposed approach is illustrated by examples of designing buildings in two styles which are well integrated with the environment.