The Sun Rain Room is a two-storey extension and restoration of a Grade-II Listed Georgian townhouse. It provides both a studio for the practice and a home for the partners of Tonkin Liu and family. The rear Extension works over two floors, with a small lightwell, bridged by a glazed stair, allowing light into the new basement. At street level, a sweeping roof with glazed walls to the garden and mirrored rear storage walls provides a social space for both the home and the studio.
The roof is a novel structural concept using the structural depth of ply sheets sandwiching an insulating core. The ply sheets are built up in layers which ensures structural continuity at the ends of ply sheets by staggering the sheet joints. It also allows for the contoured sculptural lighting holes in the roof. A thin steel support post hidden within the glazing framing allows the roof to apparently span free over the space. Given the experimental structural concept, the roof was carefully load tested using bags of water to represent the green roof dead load and the combined staff of Tonkin Liu and Rodrigues Associates as imposed load. Deflections were measured and were all well within predicted settlements.