This converted family home is located in the heart of Haslemere, Surrey. Our design created a new first floor extension across the entire bungalow footprint, partially built into the roof with a holistic design approach for the entire house. The reconfiguration of the existing ground floor allowed for the relocation of all principle living spaces onto the top floor as an upside-down house layout. This, in turn, allowed for the double aspect open-plan kitchen, dining and living accommodation to benefit from a level southerly garden access via a bridge link. The extension’s superstructure was built using a prefabricated, structurally insulated panel system (SIPs), which radically reduced the construction period and delivered high levels of thermal performance. A complete refurbishment of the existing building fabric and services reduced the existing carbon footprint of the property by half, despite it nearly doubling in size.