This chapter discusses the preliminary design of a building-integrated PV system. It is broadly based on a new-build project for the Cambridge Botanic Garden but has been simplified and developed (1). The intention is to provide a visitors centre/office accommodation and a bowls club under a single roof. This rather unusual combination of facilities is due in large part to the presence of an existing bowls club on part of the site which is to be demolished to make room for the new facilities.