Walworth Town Hall: bold new interiors behind roof risen from the ashes

When fire ravaged Walworth Town Hall in 2013, the roofs were lost, leaving the Grade II-listed building open to the sky and on Historic England’s Heritage at Risk register. 

More than a decade later, its renovation is done at last as part of a wider repurposing of council buildings on the Walworth Road in London’s Elephant and Castle. 

In collaboration with architect Feix&Merlin, developer General Projects has turned them into flexible workspace, with most of the ground floor open to public use in new ways, including a café/restaurant and community centre. The complex project has taken in the adjacent former Newington Library (1892) and Cuming Museum (1902), which have moved to the nearby Southwark Heritage Centre and Walworth Library, linking the disparate buildings and improving access throughout.

For Feix&Merlin, it has been an exercise in judging interventions in the historic fabric: how best to retain traces of its past, when to reinstate original designs, and when to intervene in a contemporary way. 

It has, says architect Julia Feix, been ‘a nice mix of leaving and adding’ as the practice assessed fire and water damage, and the changes needed to make its new incarnation a success. These include a relocated main entrance addressing the new Walworth Square around the corner from Walworth Road, achieved by turning three windows into doors and creating wide entrance steps overlooking the square.

The practice divided spaces into three categories of heritage significance and devised appropriate responses. This included a respectful and scholarly approach to restoring key historic areas such as the main staircase, and former library and museum, and a more contemporary interpretation in some more damaged areas, for example the 1865 town hall building and its 1902 extension.

This is clear in the café/restaurant at the new entrance lobby, where traces of the fire event are retained and celebrated as part of the building's history. Severely fire and water damaged, this has been opened up with many dividing walls removed (micro-cement floor inserts offer reminders of their presence). 

In this important new space, perimeter walls are plastered only to dado level and left with the evocative traces of the fire. Haworth Tompkins’ Battersea Arts Centre and Squire’s The Department Store projects were key reference points, it is no surprise to learn. 

The walls' edgy, distressed texture combines to good effect with the warmth of a series of new glulam arched columns supporting the CLT ceiling. The as-found approach to the walls has also been used in other damaged areas of the building.

Striking new exposed roof structure at Walworth Town Hall

The boldest intervention is in the badly damaged former council chamber, above the café/restaurant space. It has been repurposed into a spectacular office space, rising 10.5m to a striking exposed roof structure, and overlooked by a horseshoe-shaped gallery.

Feix&Merlin worked with structural engineers Heyne Tillett Steel (HTS) to create the new roof, which has a truncated pyramid form. As with all replacement roofs in the town hall, this follows the original roof massing and Welsh slate-clad appearance externally, but there the similarity ends. 

While the lost roof was built traditionally in timber and obscured from the council chamber by a ceiling, the new one was created in glulam and CLT and conceived as a main interior design feature, with a central grid of illuminated recessed panels surrounded by timber soffits.

‘We had to stick to the original shape and height, but wanted to keep it exposed, and for it to be timber,’ says Feix, adding that the aim was for it to be as beautiful as possible. As throughout the project, CLT and glulam appealed for sustainability and aesthetic reasons, with steelwork kept to a minimum.

‘We’re building the original mass of the roof, but we’ve done it in a modern way while using traditional materials,' says Jonathan Flint, a senior associate at HTS. ‘Rather than the sawn-timber roof trusses of the 19^th century, we‘ve taken a modern approach to an old material.’

For the new roof structure, the engineers used a concrete ring beam that had been installed immediately after the fire to secure the walls in the absence of the roof. Four glulam two-directional trusses spring from this to span the 13.5m x 13.5m space, each 240mm wide, with slender carbon steel tubular bracing elements to keep the structure as open as possible in the middle. The sides are formed in CLT slabs of spruce.

‘Because it’s quite square, the arrangement is that we have two trusses in each direction forming the box,’ says Flint, adding that by using the timber mostly in compression, and the steel to take the tension, the design plays to the strength of both materials. The trusses, prefabricated by B&K Structures, arrived onsite by road and were craned into place over just a couple of weeks. 

'Emulating the rooflight we couldn't have'

The structure combines with a central lighting grid feature. With a glazed lantern ruled out due to maintenance considerations, the architects chose an array of nine illuminated stretched panels below the CLT roof panels. ‘We wanted to emulate the rooflight we couldn’t have, so went for Barrisol,’ says Feix. 

The temperature of the lighting can be varied as desired from a warm 2700K to cool 4000K. Here, as throughout the project, the CLT and glulam is treated with a white wash fire protection. The flat roof panels in the centre are installed on a 1:60 pitch to encourage rain run-off.

The other major intervention to the chamber is the new horseshoe gallery, which is cantilevered out from the wall, supported in the corner by diagonal members. It replaces a much narrower original balcony that overlooked the chamber on one side. 

The architects took inspiration from a surviving fragment of railing, enlarging the decorative motif to form the CNC-cut, raw steel balcony front. Working with Stephen Levrant Heritage Architecture, the window surrounds were recreated with reference to a surviving remnant. 

Walls are repaired in a traditional lime plaster except in upper areas, where brickwork is visible. Levrant was also involved in the repair specification for other key heritage areas in the group of buildings, including the library, museum and main staircase. Throughout, a new Victorian-inspired colour scheme of blue, sage green and damson has been introduced.

The design team took a different approach in the new roof for the adjoining town hall extension wing of 1902, where the fire began. While again working within the recreated original roofline, the space behind this was enclosed to create a lightweight storey of extra office space. 

HTS achieved this by adding a series of glulam columns and beams sitting on the original masonry spine wall of the building. This in turn supports the new CLT roof, with more CLT forming the mansard, dormers and pyramid turrets. Inside, the effect is warm and cocooning, with the distinctive aroma of wood.

The embodied carbon of all the CLT and glulam in the former council chamber and town hall extension is 97t CO₂e. This compares with an additional 68t CO₂e if it had been built in steel frame and concrete metal decking slabs. 

It is the first time the architects have used CLT, and they are clearly big fans. ‘I love it. It’s such a beautiful material. I can’t sing its praises more,’ says Feix.

Traditional replacement for Walworth's third lost roof

A third lost roof, on the corner of the Walworth Road, was reinstated by the council in a traditional timber construction design and topped with Welsh slate. Feix&Merlin added insulation and spruce lining to match the CLT in the council chamber. 

After a five-year gestation, the town hall is off the Heritage at Risk register and beginning its new life, with space for 550 workers in flexible offices and co-working desks. The architects have clearly worked hard to increase accessibility from 24 to 60 per cent, linking up the various buildings and opening up the ground floor space as much as possible. 

Along the way, they’ve risen to the challenge of destroyed roofs, fire and water damage, asbestos, and lots of unknowns to create an appealing mix of workspaces and public spaces with contrasting characters. 

‘Considering what we found, it’s been a fairly smooth ride, says Feix.