The proposed paper will give a typological account of the nature of continuity and transition in the built environment. This theory of types claims that architecture is created and experienced within a framework of inherited formal norms. Types are defined as sets of rules for the design of buildings which are established historically - in the process acquiring a collective value to a particular culture - but which remain open to change. In order to elucidate these notions an analysis has been undertaken of a representative example of the traditional operation of types, the 17th Century Parisian aristocratic house or 'hotel particulier'.