Architects: Allies and Morrison

Allies and Morrison were commissioned to further develop Terry Farrell and Partners’ master plan to revitalize Sheffield’s city centre. In creating something like a citadel, they have significantly increased the building density of the centre whilst developing squares and routes throughout. There are new offices, a 33-storey residential tower and, at the south-east corner, the Charles Street multi-storey car park, the subject of this article.



The building appears to cut into the podium of the citadel to the north and west, with Arundel Gate forming the eastern boundary. Pedestrians access it from the podium; cars enter and leave via Charles Street in the south. A spiral ramp takes vehicles to the first-floor level, after which straight ramps take over. At the lower ground-floor level a double-height volume rises to the underside of the first-floor slab. Cutting into this partly subterranean space is the curvilinear volume of the spiral ramp, which adds spatial drama and surprise. The planned shop in this location should generate some much-needed street life on the Arundel Gate side of the citadel.


What provides the real interest in the building, however, is the cladding. It forms an uncompromising homogeneous surface to the building’s cubic volume. There is an interesting contradiction here, as when a plain, demure woman wears a glitzy, metallic cocktail dress. The effect makes for a bold architectural statement.


The building derives its visual frisson from the exquisite complexity of the cladding. Perhaps the apparent randomness in the panel arrangement is generated by a clever computer algorithm, but in fact each individual panel is identical; it is simply rotated in one of four orientations. This expresses the contemporary manufacturing concept of using simple rule sets to create bespoke mass production.


The panels are of cut and folded aluminium plate based on a 1.2-metre grid. On the inside, they are painted a lime green, while outside they have a silver anodized finish.


Each panel’s tilt creates an opening of about 30 per cent of its area, which allows for natural cross-ventilation while keeping out most of the rain. The views in and out are likewise restricted by this arrangement, giving the viewer the occasional interesting vista.


Each of the 3,692 cladding panels hooks on to a simple external framing system that connects the floors. This means that the cladding panels do not express the underlying superstructure of the building, a decision that allows the purely abstract sculptural quality of the volume to dominate.


Glazed curtain wall panels of varying degrees of opacity clad the ground-floor retail areas, giving this elegant and sophisticated addition to the architecture of Sheffield a svelte finish at street level.

Christopher Croazzo Hill