XUL Architecture were commissioned to refurbish and extend this ground and lower ground floor flat of a large Neo-Georgian detached house in London, NW3. Our aim was to create a functional and contemporary interior layout, to accommodate the needs of the clients and their wider family, while maximising the introduction of natural light into all spaces. The ground floor area was increased by 31 sqm (333 ft2) by a single storey side extension and a single storey rear infill extension. The basement area was increased by 230 sqm (2002 ft2) in order to accommodate a play room, a gym, a home cinema and additional accommodation. Two generous light wells were added to the basement, adding significant natural lighting.