Extension of an existing two storey mews building to create a new high specification four bedroom family dwelling with outdoor space. After consultation, it was felt that the most appropriate approach would be for a new contemporary building to replace the existing adequate but unremarkable inter war mews building with two new west facing terraces at basement and second floor levels. Excavation of the basement created a new 70 sq. m living room with the kitchen area semi-screened by a full height island unit. Fire engineering enable this area to be open to the entrance hall at ground floor and for the space to benefit from the diagonal weep of light extending from mews façade to oversize courtyard doors to the rear. Sedum roof warmed by the gentle extract of the CHP boiler below and punctured by a mirrored oversized roof light which brings light down through the open tread stair to the entrance level of the building.