United Kingdom House is a Grade II Listed building dating back to the early 1900′s, located on Oxford St, central London. In the 1970′s the building was extensively redeveloped behind a retained facade to create conventional office space on the upper levels (floors two to seven), arranged around two naturally vented light wells. Large retail units occupy Ground and First floor levels. Dyer’s proposal begins with the modernisation of the roof top plant, thereby reducing its size and freeing up space for four penthouse apartments to be sensitively located at roof level, with minimal impact to the existing height and mass of the building. A new glazed door within an existing opening will provide a new, dedicated entrance to the apartments, without disrupting the existing historic facade, with lift access up to the apartments. The apartment volumes are created through the use of a lightweight steel structure, with a curved roof which significantly reduces the impact of the residential building when viewed from both the street level and upper floors of adjoining buildings. Each apartment has a mezzanine floor that sits over the access corridor allowing ‘clerestorey’ light to be introduced into the courtyard space. A glazed curtain wall system will be used to create the wall between the apartment corridor and the light well. The key feature of the apartments is they way they maximise the potential of the location, by opening up to allow panoramic city skyline views across London. Full height glazed sliding doors form the principle elevation, allowing the internal space to open out into a large rooftop terrace. High performance glass and blinds will be incorporated into the elevation design to significantly reduce solar gain in the apartments. The proposal also include partially filling the light wells to create additional lettable office space. The office plates will step from level two to create external terraces on each floor. Dyer and the team recieved planning approval for the proposed scheme from the City of Westminster in March 2013.