Sensitively adding an elegant 20,000sq ft extension on top of a meticulously restored 1910 department store, the redevelopment of Arding & Hobbs has won wide acclaim for breathing new life into a once run down Grade II listed building. Adding a new, spacious, light-filled pavilion, it has achieved a BREEAM Excellent rating, and showcases how a structural timber and hybrid solution can help clients meet modern standards of sustainability while reinvigorating historic buildings for the 21st century.
B&K Structures completed the cross laminated timber, glulam and steelwork elements of the extension works on behalf of Knight Harwood and W.RE, alongside Stiff + Trevillion Architects, AKT II and Stora Enso.
The redevelopment of the century-old Arding & Hobbs department store represents a retail renaissance that has seen the once run-down Grade II listed property, in the Clapham area of South London, restored to its former glory and crowned with a two-storey rooftop Pavilion, creating valuable new commercial space.
The £48M project was led by London-based real estate company W.Re, with Stiff + Trevillion chosen as architect, due to their extensive retail and commercial experience. Knight Harwood were selected as main contractor and B&K Structures (BKS) - as the leading structural timber and hybrid structural specialist in the UK - were awarded the contract to design, manufacture and erect the engineered timber and steel upward extension, meeting the aesthetic, planning and logistical challenges with an elegantly detailed solution.
While AKT II delivered the scheme for the extension to stage 4, BKS took responsibility of the final design and manufacturing for the CLT and the glulam diagrid roof extension, utilising Stora Enso SylvaTM kit of parts, as well as delivering the structural steelwork and the mezzanine metal deck. This hybrid structural timber and steel system marries and takes advantage of the benefits of both materials. The resulting roof extension is an exemplar of the potential offsite solutions can bring to refurbishment schemes.
The refurbishment aimed to return it to its former place in the community - removing a 1970s canopy, restoring old features (including a clock tower, barrel vaults and stained-glass dome) and adding a new CLT-framed roof pavilion clad in scalloped brass. Inside, workspaces sit above a retail base, reinforcing an upward shift in the area’s appeal to business tenants.
New extension floors 4 and 5 create 10,300 and 9,700 sq. ft. respectively and exposed timber offers proven biophilic benefits as well as open-plan flexibility of use. Future tenants have access to extensive new roof terraces, which are set back from the building perimeter to minimise its visual impact from street level. Aiming to increase the area’s biodiversity, the Pavilion also features a 4,500 sq. ft. green roof and solar PV.
Deep section glulam beams were specified for their visual impact and spanning capabilities, while the CLT floors offer strength, resilience and good sound transmission properties. Both can be left self-finished, reducing ongoing maintenance, and have proven biophilic properties to enhance occupant well-being. The new steel columns align over the originals and also carry a metal mezzanine. A hybrid timber and steel solution proved to be an ideal combination for a complex refurbishment of a listed building, which required minimal strengthening but had high sustainability targets.
The client targeted a BREEAM Excellent rating, where both embodied energy and energy-in-use are key criteria. The inherent airtightness of CLT’s overlapping joints delivered test figures in line with PassivHaus standards, and the 201.9m3 of CLT and 94.6m3 of glulam are PEFC chain of custody certified, sequestering 202.7 tonnes of CO2e. Thanks to the responsible management of European forests, all of the timber will have regrown in just 65 seconds. The CLT and glulam are categorised A+ in Europe for improving indoor air quality, with very low VOC levels, and have the ability to mitigate high humidity as well as providing thermal mass to moderate temperatures.
Achieving BREEAM Excellent, Arding & Hobbs sets a benchmark for how offsite manufacturing can help clients meet modern standards of sustainability while reinvigorating historic buildings for the 21st century.
“This project is significant not just from a technical point of view, but also as a re-imagination of the ‘high street’ – department stores are an ‘endangered species’ with Arding & Hobbs being an iconic example. They were built in a different era with one purpose in mind so are very difficult to retrofit effectively. However, I believe Arding & Hobbs will set the precedent for what is possible in many more future developments.”
Valentina Galmozzi