Iain Wadham, project associate, explains, ''We understood that Westminster would require a traditional design approach to Bentinck Street. In this case we found that by drawing on established architectural design tools such as rhythm, mass and proportion we showed historical and contextual respect; this then enabled a departure to a more contemporary approach in its detailing. The balance is very important to enable the building to proclaim itself as new whilst having sufficient respect for its neighbours.”
Internally there was more scope for design freedom. A lightwell has been sunk mid-plan, such that from basement level one is treated to a view rising six stories to roof level. At second floor the main accommodation and that of the mews has been separated via an external 'green roof' area and a minimal glazed link. The external skin to the mid-level green roof is a fully glazed curtain-walling system with sliding oak louvre panels. The louvre panels, Iain explains, 'have arisen from a planning requirement for some opacity, countered by an environmental and energy-saving need for as much natural light as possible.'
The design team made sure the building has a low-energy performance. The internal lighting loads are reduced by locallised dimming according to the amount of natural light entering, and are also zoned via movement sensors ensuring that any zone left unused is not left with its lights on.
In addition, during the summer, a pumped water loop takes unwanted heat from the air-conditioning system and rejects it underground via coiled tubing in three 150m deep boreholes, returning to the surface cooled. In the winter, the benefits are reversed with the cold water going down being 'pre-heated' by the earth on its return.