The building type is a (knowledge) structure that is both recognised as a constitutive cognitive element of human thought and as a constitutive computational element in CAAD systems. Questions that seem unresolved up to now about computational approaches to building types are the relationship between the various instances that are generally recognised as belonging to a particular building type, the way a type can deal with varying briefs (or with mixed functional use), and how a type can accommodate different sites. Approaches that aim to model building types as data structures of interrelated variables (so-called'prototypes') face problems clarifying these questions. It is proposed in this research not to focus on a definition of'type,'but rather to investigate the role of knowledge connected to building types in the design process. The basic proposition is that the graphic representations used to represent the state of the design object throughout the design process can be used as a medium to encode knowledge of the building type. This proposition claims that graphic representations consistently encode the things they represent, that it is possible to derive the knowledge content of graphic representations, and that there is enough diversity within graphic representations to support a design process of a building belonging to a type. In order to substantiate these claims, it is necessary to analyse graphic representations. In the research work, an approach based on the notion of'graphic units'is developed. The graphic unit is defined and the analysis of graphic representations on the basis of the graphic unit is demonstrated. This analysis brings forward the knowledge content of single graphic representations. Such knowledge content is declarative knowledge. The graphic unit also provides the means to articulate the transition from one graphic representation to another graphic representation. Such transitions encode procedural knowledge. The principles of a sequence of generic representations are discussed and it is demonstrated how a particular type - the office building type - is implemented in the theoretical work. Computational work on implementation part of a sequence of generic representations of the office building type is discussed. The paper ends with a summary and future work.