The Black and White building_WTA_TOG_4_photography by Ed Reeve ©
The new tallest timber building in the City of London, incorporating a German engineered wood structure and American hardwood high tech brises soleil, has officially opened.
The Black & White Building in the borough of Shoreditch was designed for leading UK workspace provider The Office Group (TOG) by architects Waugh and Thistleton (WTA), which has built up an international reputation for its cutting edge timber-based projects.
The 17.8m, seven-storey office block features a core structure of CLT panels made by Zublin – even the lift shaft and stairway are made in the material. The manufacturer also supplied the glulam frame for the glazed façade. The structural beams and columns comprise beech BauBuche laminated veneer lumber from Pollmeier.
TOG has a total of 72 workspace properties, covering 3.1 million ft2, but the Black & White Building is its first purpose-built premises. Up until now it has refurbished existing premises.
“Perhaps it was a bold move to go for timber our first construction project,” said TOG co-founder Charlie Green. “But since we started TOG 20 years ago, we’ve wanted to distinguish ourselves in the office rental market through better design, that’s been our north star, and we see environmental performance as central to better design. So in the Black and White Building we wanted to push boundaries further. We wanted to be different and to make statements about what we believe in and feel is needed in the real estate industry. We wanted to create a building that would challenge the norm and demonstrate that you can build better.”
The Black and White Building is WTA’s 28th mass timber project and project architect Dave Lomax said that awareness such structures can – and should – be built in wood is growing.
“Ten years ago when I started working with WTA founders Andrew Waugh and Anthony Thistleton, we were pushing clients to adopt timber when, really, there was nothing else to compel them to do so,” he said. “I’m delighted to report that now, nine times out of 10 when the phone rings it’s someone who already sees the benefit of this approach and is simply asking for our help to make it happen. They also need to convince their board, lenders, their insurers and a great many other gatekeepers this is the way to go. Even here though we’re seeing change, with major funds identifying the threat to their business of holding assets that may not meet coming ESG reporting requirements, or might be subject to carbon taxes in the future. So sometimes it’s now gatekeepers opening the gate and pushing unconvinced developers through!”
Mr Lomax added that it was ‘absolutely correct’ that construction should be ‘doing more with less’ and that included timber. Up against materials that are more ‘cheaply available’, to be cost competitive WTA had focused on ‘designing in ways that do not encourage structural gymnastics or costly transfer structure’. “The challenge of being cost competitive has directed us to understand the most efficient way to engineer a column grid to make optimum use of a material’s strength before weight adds a burden,” said Mr Lomax.
“The interesting thing is all these efficiencies could equally be applied to concrete and steel structures, but typically are not. This is due to the perceived cheapness and expendability of the materials and the view ‘this is how we always do it’. And if we’re talking about running out of raw materials, let’s focus first on the ones we cannot regrow, like sand used in concrete.”
Using BauBuche in the Black and White Building, as opposed other engineered timber products, he acknowledged had come at ‘an increased capital cost’. But due to its strength, beams and columns could be slenderer.
“The reduced beam depth and footprint came with trade-offs, like a lower building height, so less cost in cladding, and increased lettable area,” said Mr Lomax. We also explain to clients that foundations get smaller with lighter timber construction and programmes get around 20% faster – and if you’ve borrowed to build, then a 20% shorter programme is real money in hand.”
The brises soleil are made in thermo-treated American tulipwood from Northland Forest Products, with each fin designed using parametric modelling and mounted on the façade according to the angle at which sunlight hits the building. The system maximizes natural light in the building, while minimizing solar gain.
The American Hardwood Export Council took an advisory role in the specification of the material, which is one of the most abundant species in the US hardwood forest, comprising 7% of all trees. It highlighted that previous exterior use of the timber in thermo-treated form showed it was durable, stable and strong. Further tests had also demonstrated that it could be effectively treated with fire retardant.
“Tulipwood ages in a pleasing, gentle way too – and we’ll be back to record the process as a reference for other projects,” said AHEC European Director David Venables.
He added that it had been ‘tremendously exciting to be involved with the Black & White building’. “It’s underlined the range of solutions timber products can offer and how they can all work collectively and effectively together,” he said. “It’s also emphasized the importance of teamwork in such a project. It was driven by an architect with a vision for timber to deliver a building that satisfies the regulations, looks good and performs, but everyone involved was also determined to make it work.”
In total, the Black & White Building uses 1,330m3 of timber, stores 1,015 tonnes of CO2 and delivers an embodied carbon saving over an equivalent concrete structure of 37%. Moreover the main timber frame was erected in just 14 weeks by an engineering team of six.
Mr Green said it more than exceeded expectations and that TOG saw it as a model for future developments. He also maintained that the fact that it is a timber-based workspace actually attracts occupants.
“This building just appeals to people and it can benefit their businesses as it speaks to their brand and their ethos if they can say to clients ‘we’re in the City of London’s tallest timber building’ that represents a 37% embodied carbon saving on a steel and concrete equivalent,” he said. “So we’ve shown you can create a building that’s sustainable, beautiful and commercial. We’d budgeted for full occupancy in 12 months after the January opening. But we were at 55% after six weeks!”