Top of the Tree

“Every time we complete another significant timber building, it really helps us spread the message that this is possible,” says Andrew Waugh, director of Waugh Thistleton Architects. His latest project, the Black & White Building in Shoreditch, is indeed significant, since it can now boast of being the tallest all-timber office building in central London; more than that, though, it heralds a new sense of the great potential of mass timber to become a more sustainable alternative to concrete and steel.

Waugh’s client is The Office Group (TOG), which until now was better known for sensitively retrofitting existing buildings, from the mid-20th-century former BBC office, Henry Wood House, to the art deco Summit House in Holborn. After 20 years, this is TOG’s first “ground up” project, and one it is very proud of. “The Black & White Building represents a major step forward for us, and – I hope – the wider industry too,” says TOG’s co-founder Charlie Green. “It’s a statement of who we are and how we will approach sustainability.” The new building replaces an existing TOG location (and retains its original name), which was deemed unsuitable for further extension or refurbishment.

So, how do you build tall using timber – a material that, on its own, is not as strong as steel or concrete – as a structural system? The building’s core is made from cross-laminated timber (CLT), which is essentially a sandwich of thin planks, glued together in perpendicular layers to create incredible strength; while a frame built around the core is made from laminated veneer lumber (LVL), braced with CLT floor slabs. LVL is not a well-known building material in the UK: Waugh describes it as “a high-performance version [of CLT], made of thin peeled layers of beech. It’s super strong, so the beams and columns can be nearly the same size as comparable steel sections. We could use the minimum amount of material for maximum structural and aesthetic benefit.” The elegant timber louvres on the outside of the building, used to control solar gain, are made from tulipwood that has been thermally modified to make it more durable.

The result is a building with 37% less embodied carbon than a similar structure. This is not only down to the timber itself but the on-site construction: CLT is lighter and easier to transport than concrete and steel, meaning fewer deliveries (which is also a bonus in urban areas, where traffic and access can be difficult). The building is also powered by 100% renewable energy, including 80 solar panels on the roof.

There are six storeys plus a further basement storey, and the building is 17.8m high at its tallest point. Within its walls are 28 offices of different sizes, six meeting rooms and various break-out areas; a first for TOG is a dedicated studio for activities including yoga and meditation, a sign of the times as to how work and wellness have moved closer together, with a focus on nourishing mind, body and soul amid the daily grind. The interiors, by Daytrip Studio, reflect the same story, with exposed timber and natural textiles designed to soothe.

TOG has gone out on a limb to demonstrate how the future of office building could look – a beguiling mix of one of the world’s oldest building materials and modern engineering. Waugh says that the project “clearly demonstrates that mass timber is a viable replacement for concrete and steel in the mainstream office market, saving thousands of tonnes of CO2.We’re trying to change the way we build, to transform the industry.”