Total transformation of 1980s duplex penthouse results in attractive open-plan interiors and vastly improved layout

​​​​​​​Reconfiguring the stairs was a major  contributor to resolving circulation problems in the original layout of this duplex penthouse. Architect Andrew Wilkinson removed the existing framed-in spiral staircase and replaced it with a suspended brass and walnut staircase that presents a striking sculptural element on entering the apartment.