Refurbishment and Adapative Reuse winner

Designed by Foster + Partners, The Whiteley is a vibrant mixed-use development that has breathed new life into an iconic Grade II listed former department store in Bayswater, west London. The £1bn scheme comprises residential, retail, leisure and hospitality accommodation organised around a public courtyard. Delivered by specialist contractor Propak Architectural Glazing, the complex heritage façade package included the design, manufacture, testing, and installation of 167 bespoke, thermally-broken steel windows. 

Reconciling the original window proportions with modern thermal, acoustic, and weather performance standards was one of the principal challenges. Working closely with Schüco, Propak adapted the Jansen Arte 66 system to accommodate window sizes of up to 4.3 metres in height and spans of up to nine metres across floor slabs in the north and south cupolas. Despite the scale of the units, ultra-slim sightlines – some as narrow as 25mm – were retained to meet the stringent conservation requirements. 

Custom reinforcements, including laser-welded steel plate mullions and add-on extrusions, were developed to replicate the original detailing and deliver exceptional performance. Each window was individually handcrafted and precisionwelded, with configurations ranging from arched-head and bay windows to convex and concave geometries. Unique fixing details were created to accommodate structural movement between the new steel frame and the retained façade, with extremely tight tolerances due to the confined site and scaffold interface. 

Where possible, Propak reclaimed and reintegrated original cast iron mullions, fascia panels, balustrades and ironmongery. In cases where salvage wasn’t feasible, 3D modelling and casting techniques were used to produce exact replicas. 

The upgraded window system underwent full-scale visual and performance testing in Switzerland, successfully meeting demanding benchmarks for air, wind, water, acoustic, and thermal performance. By retaining and upgrading the original façade, the scheme significantly reduced embodied carbon while preserving the architectural heritage. The Schüco Jansen Arte 66 steel system facilitated large spans and high-performance glazing, bringing daylight deep into the building and greatly improving energy efficiency – without compromising the historic fabric. 

The jury applauded the project for its meticulous and technically-accomplished approach to heritage façade refurbishment. It was particularly impressed by the skilful adaptation of a standard Schüco window system to achieve expansive openings and ultra-slim sightlines, all achieved in tandem with stringent performance and conservation requirements.