A Sheffield urban regeneration project featuring hundreds of Kawneer windows is one of the six finalists for this year's RIBA Stirling Prize, the Royal Institute of British Architects' highest accolade.
Kawneer’s AA®3110 horizontal sliding windows complement multi-coloured feature aluminium infill panels on new apartments on the 13-storey, west- facing flank of Park Hill, the 1950s solution to Sheffield slum clearance which itself fell foul of current-day social issues and was on a downward spiral to demolition.
When it was built in 1961, Park Hill was the first successful slum clearance scheme of an entire community in Britain after the war, and radically modern. It replaced row upon row of dilapidated back-to-back terraces and tenements with shiny new flats complete with indoor toilets and central heating for 2,500 people.
Architects Ivor Smith and Jack Lynn had been inspired by Le Corbusier’s Unite d’Habitation in Marseille which resulted in innovations including the “streets in the sky” – access decks wide enough for milk floats that were intended to replace the community feel of streets on the ground.
But by the 1980s the estate had become a byword for all that was wrong with local authority housing and many people prayed the council would knock it down. Instead, in 1998, English Heritage gave it a Grade II listing, making it the largest listed building in Europe.
Ultimately, however, Urban Splash were selected as preferred development partner through a public sector selection process and working with architects Hawkins/Brown and Studio Egret West have now transformed the once notorious council estate into almost 1,000 apartments as well as 140,000²ft of offices and retail and leisure facilities.
This involved stripping the Grade II listed structure high on a hillside behind Sheffield station back to the bone, a job made even more difficult because the concrete frame could not bear the weight of demolition plant so the work had to be done by hand.
The cladding was transformed by replacing the original brickwork with anodised aluminium panels that replicate and exaggerate the subtle beige, ochre and plum coloured banding of the brickwork.
The Kawneer AA®3110 windows were installed by approved specialist sub-contractor SG Aluminium. They were designed to maximise ventilation and safety without detriment to smooth operation. They are substantially larger than their predecessors and are glazed with a single pane compared to the multi-paned originals.
The windows have been enlarged from one third to two thirds of each panel of the concrete frame grid, allowing more light into the spacious one-, two- and three-bedroomed apartments which offer stunning views over the city.
These are complemented by the anodised aluminium panels in a range of colours that look different depending on the light, angle and distance from which they are seen.
This year's Stirling Prize winner will be announced in a special ceremony in London on Thursday 26th September.