Foster and Partners has completed a radical reworking of its design for the Greater London Authority hq, just in time for submission of the planning application yesterday (Wednesday). It has been refining the design since winning the competition with a proposal which was still at a relatively schematic stage. But it is only recently that the design reached a point at which the office felt that it would benefit from a fundamental re-think - something which few offices, not having Foster's resources or experience - would attempt at this stage.
But the hard work has paid off, with a far more integrated design. The original, very separate 'mask' - needed to satisfy the environmental considerations - has shrunk and is now much better blended with the rest of the cladding which wraps round the building, allowing the architect to describe the building as 'omni-directional with entrances on the north and south as well as from the sunken terraces'. Instead of facing towards Tower Bridge and the City, turning its back on other aspects, the building now addresses all directions of the city which will be governed from within it.
The sunken terraces link the main central space of the London Bridge City masterplan (also by Foster) to the gla headquarters, which will be the first element of that masterplan to be built. The gla building has nine storeys plus lower-ground and ground floors, and will accommodate an assembly chamber, gallery, public library, committee rooms, administrative offices and restaurants, in a net floor area of 12,000m2. The public will have access to the triple-height north entrance foyer, and to the lower-ground, ground, first and second floors via dramatic encircling ramps. These allow free access by disabled visitors and also offer panoramic views.
The debating chamber will be in the form of a dramatic nine-storey 'flask' reaching right to the top of the building, and will provide the focus for the entrance foyer, with ramps circling around its perimeter. There will be a visitor centre and a flexible exhibition and function space at the higher levels, with a public viewing gallery at the top.
The form of the building is part of the energy strategy, says Fosters, 'minimising perimeter surface area to reduce heat-loss and heat-gain'. There will be perimeter openable windows, a low-level air supply and passive- and borehole-cooling; the double-glazed cladding envelope will incorporate photovoltaic panels and sunshading.
Ove Arup & Partners is the structural, services and acoustic engineer. Davis Langdon & Everest is the cost consultant.