This project involves the extension and remodeling of a 1930s end-terrace house in South London, referred to for its unusual use of timber cladding as the Slat House. The client specified an extension which would open up the interior of the house during the summer, making a greater connection with the garden. They also wanted a ‘tough’ and flexible series of internal spaces, which are able to adapt to the changing needs of a growing family. On the ground floor an expansive space is cut through the house, creating a vista from the entrance through to the rear garden. The spaces can be separated and reconfigured with large sliding panels. The new extension houses a large kitchen and dining area with in-situ concrete floors and walls and a bespoke concrete worktop and breakfast bar. A dramatic new window frames the garden and a large sliding door gives access to the new terrace. A new room at the front of the extension, lined with birch-faced plywood functions as a work studio and garage, accessed from the front via a giant swing door. The internal finishes of the extension are pulled through into the main house, emphasizing the new open plan arrangement of the ground floor. Timber cladding was specified as a practical necessity to reduce the load of the building on its new foundations, but also for aesthetic purposes, to harmonize the extension with its wooded surroundings. The width of the red cedar panels defined a module by which all window and door openings were determined. This rigour adds to the strong exterior appearance of the building.