A complicated brief asked for a dining-room extension, a new gymnasium and a dance studio to a private house in South-west London. The project involved the design and construction of a two-storey extension gymnasium/dance studio in the basement, with dining room above. The extension is of steel- frame construction, including a steel skeletal rooflight with infill double- glazed panels and floor-to-ceiling glazing. The rooflight has a skirt of copper flashing band to the coping detail, with glazed panels above operated by an electronic glazing mechanism to provide natural ventilation on warm days. The contract sum was £80,000.