City of London, UK
A refurbished office scheme taking the original building back to frame and recladding with a new façade using Portland stone and an anodised aluminium curtain wall and rainscreen, and incorporating an additional floor
It replaces a previous 1980s office building of circa 45,000sqft and now provides 65,000sqft of Grade A office accommodation with a BREEAM ‘Excellent’ rating
The 20,000sqft uplift is a significant gain and improved use of a tight site; the project was achieved despite numerous constraints and challenges, not least of which is the location in the background of one of the St Paul’s Cathedral LVMF views.
The external envelope responds to two key drivers: townscape views and solar orientation.
The northern orientation permits the opening up the long façade along Goldsmith Street with generous full height glazing, while the flanks of the building are more solid; clad in Portland stone to sit comfortably in massing and appearance within the context in the longer townscape views along Wood Street and Gutter Lane. The lower glazing ratio limits solar gain from low east and west sun.
Sustainability was a key part of the client’s brief and the building has achieved a BREEAM ‘Excellent’ score, and an important aspect of our sustainability strategy was the retention of around 70% of the concrete substructure and superstructure of the previous 1980s office building. The structure was adapted and extended at upper levels, but the retention of the structure represented a considerable saving in embodied energy.
The M&E strategy comprises an underfloor fresh air displacement system with passive chilled beam cooling above a perforated metal ceiling. The raised floor zone is 300mm high to allow air supply but the ceiling zone is only 250mm overall This extremely tight zone required careful co-ordination at all stages of design and construction. As well as optimised zones, the system has good comfort conditions, low energy use and low maintenance costs.
Ample provision for cyclists is made in the basement with a dedicated platform lift providing access to the cycle store which has 56 spaces in double stacker racks. Showers are provided in dedicated male and female areas with one combined accessible WC and shower. A drying room is also provided.
The entrance hall palette comprises a slatted hardwood feature wall and honed limestone flooring. These are combined with a sinuous curving wall which directs the visitor towards the central lift bank.
Typical 820sqm office floorplates are efficiently planned with the core centrally located along the southern party wall boundary, providing an external aspect to all office space.
Upper floors are set back and provide accessible terraces at sixth and seventh floors. The terraces provide dramatic views to the central cluster skyline to the east and the dome of St Paul’s Cathedral to the west.
The project was winner of the OAS ‘City Development of the Year Award’ in 2015