Refurbishing a former pottery in Stoke
A former potteries factory in Stoke-on-Trent is set to become a centre of learning for refurbishment – after it has undergone a transformation itself. Jan-Carlos Kucharek reports.
There’s a pleasing synchronicity to the idea that a new training centre devoted to refurbishment skills should itself be within a refurbished building. And not just any old building, but a rare piece of 19th century industrial heritage. The Centre of Refurbishment Excellence (CoRE), in Longton, Stoke-on-Trent, set to open early next year, has been founded in the old Enson Works, a former potteries factory dating from 1842, whose four red brick bottle kilns are a distinctive local landmark. “There used to be 400 of these bottle kilns in the Stoke-on-Trent area, now there are just 40, and we’ve got four of them,” says CoRE’s chief executive Jonathan Davis.
An architect and former director of CABE, Davis has a long-standing involvement in sustainable design and is a panel member on the government’s Green Construction Board. For him, a new construction skills centre in a historic building refurbished to BREEAM “very good” standards is a poetic pairing. “The kilns look evocative, even in their run-down state,” he adds. “They’re going to make for an incredibly powerful space.”
The derelict Enson Works and the adjacent American Hotel, formerly the works pub, were identified for regeneration and bought by the city council in 2009. To create CoRE, a not-for-profit national centre of learning and skills development for the refurbishment sector, a partnership was then set up between the council, the Building Research Establishment and Stoke Studio College for Construction Excellence. This is backed by funding from the European Regional Development Fund, central government, the city council and industry partners, including energy provider E.ON.
The Hub, a new-build construction training college, opened in autumn last year. The next and final phase is the refurbishment of the Grade II-listed factory, plus piecemeal 1930s additions, into a state-of-the-art conference facility.
New floors will be inserted into the building and enclose what used to be an external courtyard between the kilns, creating a demonstrators zone for innovative products, materials and systems at ground level, and a bright rooflit conference facility and reception spaces on the upper level. Light will be transferred down via glass blocks set into the concrete floor.
Creating the Hub, the new training college element of CoRE, involved the resiting of the factory’s American Hotel
The re-use of the bottle kilns is both novel and ingenious. At ground floor level, where they are widest, they will act as dedicated audio visual, meeting and display spaces. From first floor, as they narrow, they will act as stacks for the building’s natural ventilation strategy. Each has been enclosed by a square of steel beams to ensure the increased floor loads are transferred onto these instead.
Contractors John Paul Construction and Graham had a considerable task: rain had for years poured through the broken slate roof, so the whole building fabric had suffered decades of compounded decline and neglect. And as a listed building, both English Heritage and local conservation groups were keen to ensure that remediation was carried out sensitively.
A steel grid encloses each kiln
The first priority was to ascertain the condition of the brick facades and steel structure, which had a grid of roughly 4m, bearing off the irregularly placed bottle kilns.
“Corrosion was endemic,” says David Dobson, project director for CoRE at Stoke-on-Trent City Council. “When we started shotblasting the steelwork to clean it, some literally disintegrated before our eyes. But where we could, the decision was always to strengthen the existing steel with new flange and web pieces rather then replace them.”
The first floor of the factory comprised 1930s precast concrete slabs whose reinforcement was heavily corroded, which were either treated and refaced or replaced. But to make the building more sustainable, they had to be less forgiving with the ground slab, which was jack-hammered out. “We had to cast a new slab at a lower level, adding in a layer of rigid insulation, under floor heating pipe runs and then a screed layer — its u-value has improved immensely,” says Dobson.
Refurbishing the brick elevations was also a big task. To cope with the increased loading bearing requirements, all the brick walls were underpinned along their length using injected polymer grout to stabilise the soil beneath. Concern for heritage and authenticity meant they had to go the extra mile. “We spent a lot of time sourcing the right type of replacement bricks from reclaim salvage works, and then learning to work with lime mortars — a skill seldom seen now,” says Dobson.
In probably the most dramatic move, the American Hotel was dismantled brick by brick, re-sited and faithfully rebuilt to allow the construction of the new Hub building on its site. Replacement Imperial-sized bricks were painstakingly sourced, as were its sandstone lintels and mullions and bosses, including hand-carved curved lintels at the entrance. Its days as a drinking hole over, it will now form part of the impressive and spacious demonstrators zone.
CoRE’s Jonathan Davis says the local community has been fascinated by the works to the bottle kilns, which for more than two centuries shaped the skyline of part of the city. Dobson adds: “It’s a credit to everyone involved. This project has achieved so much so well, since it was first announced in January 2010. Not only is it bang on time for the Green Deal, as a building, it’s bang on the money.”