Quality and process improvement programs usually require organizations to run a repository such as an experience base. However, setting up the schema of an experience base requires expert knowledge. But schema experts are not always available to support the setup of a new experience base. One promising solution is to capture their knowledge in patterns or building blocks. An initial collection of such building blocks is systematically documented in the PLEASERS (Product Line Approach for Software Engineering Repositories) library. In this article we describe the underlying conceptual model of the PLEASERS schema building blocks. Schema experts can use the introduced model to create sets of schema building blocks representing their knowledge.