Designed by Waugh Thistleton Architects for The Office Group, the Black and White Building offers a sustainable home for offices in East London.

Words
Jason Sayer
Photos
Jake Curtis

On Rivington Street in Shoreditch, you can find 1,774 trees. You’d be forgiven for not immediately noticing them, for a combination of beech, spruce and pine trees has been expertly machined and crafted to form a building. The building in question is 74 Rivington Street, Central London’s tallest mass timber office building, designed by Waugh Thistleton for office space provider TOG (The Office Group).

That many trees may sound like a lot, but building this way is significantly better for the planet than using concrete. Indeed, had the latter been opted for as the primary building material, an extra 1,000 tonnes of carbon dioxide would have been emitted in construction due to the embodied carbon associated with concrete, saving more than one third of the construction carbon cost.

As a result, TOG’s latest offices see a proudly timber structure rise 17.8 metres, accommodating six floors and space for 28 offices, including a yoga studio, bookable meeting rooms, break-out spaces, showers, a roof terrace, and storage for 94 bikes. Externally, the building has been clad in thermally modified tulipwood louvres — kiln baked and dried out to be chemically inert — which work with glulam-framed, glass curtain walling to manage solar gain without the need for special coatings (that often end up in landfill). Such a façade system allows timber to be a key part of the building’s aesthetic – both inside and out, creating a layered envelope that hints at the internal timber structure, too.

“The depths of the timber shading fins varies floor to floor and were optimised for each elevation to ensure a good level of glass transparency was achieved without compromising on the overall energy use of the building,” Toby Ronalds, director at façade consultants Eckersley O’Callaghan told AT.

David Lomax, associate director at Waugh Thistleton, was able to expand, explaining how weather data, sun path maps, and integrated shading data from surrounding buildings was used to make a “detailed pixelated map” which was then abstracted into the measurements of individual louvre depths used around the building. Despite being a hardwood from North America, tulipwood was a viable choice given its ‘soft’ qualities and being in oversupply stateside, meaning it is often used for biofuel.  

Perimeter columns at 4.5m high, combined with a downstand timber edge beam control structural deflections on the façade line. The composite timber and aluminium curtain walling spans from floor to floor and the detailing accommodate both short deflections and long-term shrinkage of the mass timber structure. (Credit: Waugh Thistleton)

Inside, a cross-laminated timber (CLT) core has been employed in conjunction with a laminated veneer lumber (LVL) structural frame – a system which does much of the heavy lifting for the building’s embodied carbon credentials. The frame, carried out by Hybrid Structures who acted as the timber structure subcontractors, has been composed so to not impose on the building’s corners, with these being left free to afford better views out, particularly down Rivington Street. The CLT core and LVL frame also helps save carbon through sequestration. Lomax was on hand to explain: “Most of the forests in Europe are commercial forests. Very few are old-growth forests; if you have a managed forest, you have to cut it down and harvest it,” he said. “We have to put the wood that is in those forests and the carbon that it has taken from the atmosphere, in the longest lasting asset that we possibly can. And at the moment, the most enduring asset we think we have is buildings.”

So where did the structural timber for the Black and White building come from? German company ZÜBLIN Timber supplied all the LVL and CLT components, with wood being processed at the company’s factory in Aichach, one hour north of Munich. A spokesperson for the company said that more than 90 per cent was locally sourced, with one exception being the visually exposed CLT panels, for which Nordic spruce has been used for the outer layer. Meanwhile, some LVL stock known as BauBuche (more on that later) was produced by Pollmeier, another German company, being milled in Creuzberg with the beech timber sourced from forests within 150km.

Exploded detail showing how the BauBuche LVL works in conjunction with the CLT. (Credit: Waugh Thistleton)

Building this way has benefits beyond being a sustainable solution, also able to provide TOG more office space, an important factor here given the high values Shoreditch can command. “Even though LVL is more expensive than glulam, there is a trade-off between the way we can build, the building’s lettable space, and the speed we can build it — they all trade off to the point where it pays for itself essentially,” said Lomax.

A key component of making this happen was the use of BauBuche, a hardwood LVL engineered from thin layers of beech timber. The architects had used the product before, notably at Vitsoe’s premises in Leaming Spa. Here, BauBuche has been used for beams and columns for its structural strength, being partially embedded in to the CLT floor slabs, of which are 220mm thick, allowing the beam to only project 350mm below the slab. “If we had built the columns out of the same tech as the window frames, which is possible, they would be 200mm bigger in section,” Lomax noted.

According to Greg Cooper, managing director at Hybrid Structures, the CLT floor slabs “act as diaphragm floor plates that transfer the load back to the core and bracing system.” The BauBuche beams, meanwhile, sit in the depth of the floor to reduce the head restrictions within the building — the connection being formed via a shelf detail within the beam.

Each office floor has a shared kitchen area. 

BauBuche posed some problems too: it doesn’t like rain — a problem when construction started in May 2021, one of the wettest months that year. This, however was easily overcome — protective coating was applied to prevent water from damaging the material, and this adversity to wet weather is more than made up for by the fact hooks and ties can be cut into it, allowing servicing to run along it (potentially saving yet more space). In this instance the floor essentially tied the bays together, easing the distribution of services.

Furthermore, the LVL framing system meant the structure could be easily built — and even taken apart — being screwed, rather than glued, together. “Building in timber is low-tek,” continued Lomax. “We erected this with between four and six people on site at any one time; it took 14 weeks. They were driving screws into pre-drilled metal brackets or putting bolts into place. To make this way of building work, what you need is a really experienced sub-contract site manager, that’s where all the knowledge lies, making sure all the brackets are in the right place — fixing the brackets isn’t necessarily the big deal.”

The contrast of building using a timber frame compared to concrete was writ large on the project itself, evidenced with the building’s concrete basement. For this, demolition, digging and building back to ground took 38 weeks. The contrasts regarding carbon are similar as well: the timber superstructure accounts for 18 per cent of the building’s carbon impact, while the substructure accounting for some 32 per cent.

Section looking east. (Credit: Waugh Thistleton)

“This feels like the apex of a very long process, from various different buildings and installations and ideas like MULTIPLY,” remarked Lomax. “This is our 26th timber building, though only the second building out of LVL that we’ve done, but it is, architecturally, a massive leap in complexity. It does show that when those stars align, it can be done.”

The Black and White Building opened on January 17^th. Fifty per cent of the building has already been let; TOG co-founder Charlie Green expects the building to be filled by July.

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