The client wished for a heated rear extension glazed on two sides with a large opening rooflight and cavity wall with opening window along the boundary. The proposals were granted planning and a careful calculation was required to obtain Part L agreement under the Building Regulations. To do this the large fixed glazed screen and opening window were specified as triple glazed. The client choose the Junkers floor finish and also requested under floor heating, these were carefully integrated. The design was developed and specified with three tenders sought. After visiting previous projects the client opted for a Kingston based builder. The project was built for the sum quoted and the client has written references with praise for the design.