‘What you regulate is what you get’ seems to be the principle for Nouvel’s formal concept. The building appears as a singular silica block, shaped and carved by the constraints of the St Paul’s Heights and viewing corridors, first established in the 1940s, along with the site boundaries, daylight guidelines and rights of light issues. It is only one third of the height of the cathedral. I can imagine Nouvel being inspired by playing with these regulations.
Where Nouvel leans walls out he withdraws them at ground level to avoid overstepping the site boundary. Why does he lean them outwards? He is continuing the formal composition inspired by the regulations and expanding the views up Watling Street. All of this leads to a clear architectural expression at roof level which is the purest and most prominent of the building’s facets. Here the silica form easily contains the plant and monster cleaning systems.
Looking at the designs for the aborted joint Foster/Nouvel proposal for nearby Walbrook Square, dubbed Darth Vader’s Helmet, I see the same generic modelling of form. In New York, Frank Gehry took a similar approach with the IAC headquarters, analogous to a shimmering white yacht (the client’s request), which is fritted internally allowing the glass to reflect a lot of the sky. Nouvel, working with Sidell Gibson Architects, has delivered a glass building that absorbs more light than it reflects.