This mews building was originally used as a silversmith’s studio and is three storeys high including basement level, which lies below street level. This complex project connects the ground floor flat into the vaulted storage space beneath to create a two-bedroom maisonette, with the top storey flat remaining in separate ownership. One of the biggest challenges was to provide access between the ground floor and basement. The solution adopted involved cutting into the masonry vault in order to create two bedrooms and a bathroom in the basement. This meant the vault needed to be altered to accommodate an L-shaped slot to allow the construction of the stairwell and lightwell. The vault also had to be cut with glazed slots and pavement light ‘chutes’ to give light and ventilation to the lower spaces.