The Charlotte Building
Working with architects Lifschutz Davidson Sandilands we replaced an existing structure and delivered an award-winning seven-storey office building with a stylish, art deco twist to the façade, within the constraints of a tight urban site in the heart of London’s West End.
In terms of ground and substructure, we needed to work around the Post Office mail tunnels which ran directly beneath the site, communicating our programme and methods of construction with their engineers. We undertook extensive ground modelling to ensure that the new building, which was lighter than the existing one, would not induce undue ground movement.
The new basement was set at a lower level than the existing structure, but we simplified intrusive works by mainly working within the footprint of the existing basement, and reusing its existing walls. We specified a raft foundation to spread superstructure loads over the building footprint, and introduced localised thickening in the vicinity of the tunnels 9 m below.
We adopted an in-situ reinforced concrete frame for the superstructure, with the top storey set back from the street; the frame comprised flat slabs supported on columns. An emphasis on green construction methods led us to leave the soffits exposed to maximise thermal mass, as well as introducing a displacement ventilation system whereby we utilised outside air to cool the office space, without the need for mechanical methods, during colder seasons.
The attractive aesthetics were achieved using a bespoke cladding system which maximises daylight and controls solar gain. Clear glass and operable opaque panels span vertically between slabs, and we utilised transfer beams to provide the staggered edging conceived by the architects, with perimeter columns varying in size and staggered by up to 3 m. This element of the structure also serves to protect the building from the effects of disproportionate collapse.
Seven-storey office building with art deco-style façade incorporating glass and opaque panels
Lifschutz Davidson Sandilands
£ 13 million
- 2010 RIBA Award
- 2010 BCO Regional Award