There is very little about most new “sustainable” office buildings that is true to the label. Through an alchemical process of validation and certification, great carbon-hungry shafts of concrete, steel and glass are magically deemed to be “zero carbon”, and adorned with the gold and platinum medals of trade associations that exist to promote their members’ interests. The inclusion of solar panels, heat pumps, low-flush toilets and numerous other bolt-on gizmos creates an impenetrable veil of green goodness that can hide a multitude of carbon sins.
Just as covering concrete with plants does not make it green, filling a high-energy, high-rise glass office tower with low-energy gadgets does not make it carbon-neutral. Claims of “net zero” almost always mean that someone else is picking up the carbon tab. Swathes of rainforest are acquired on the other side of the planet, often with damaging knock-on effects for the environment and local populations. A recent investigation found that more than 90% of rainforest carbon offsets approved by the world’s largest provider are largely worthless – and could actually be making global heating worse.
In architecture, the focus has long been on reducing the amount of energy a building consumes once it is occupied – known as operational carbon – but the bigger factor comes much earlier in the process. Up to three-quarters of a building’s total emissions over its lifespan come not from leaving the lights on and cranking up the thermostat but from the energy consumed in the production of the materials used to build it – known as embodied carbon. That, much of the industry now finally agrees, is where efforts must be focused to avert climate catastrophe.
In an unassuming alleyway in Shoreditch, east London, stands a new office block that boasts few of the shiny gimmicks of its bloated glass and steel neighbours a few streets away in the Square Mile. But building it used almost 40% less carbon than comparable structures – primarily because it’s made of wood.
“I often come in and put my nose against the walls, just to smell it,” says Charlie Green, co-founder of flexible workspace provider The Office Group. He is sitting in the lobby of the Black & White building, its first new-build project, where everything in sight appears to come from trees. End-grain oak setts cover the floor, like a great butcher’s block, supporting chairs of ash and walnut, stools of cork, walls of raw spruce, and columns of beech, while sun-shading louvres of tulipwood cover the glazed facade. “People come into work,” he says, “and just start touching everything.”
He’s right. It is the first time I have wanted to caress a lift: the cabin is lined with sumptuous panels of cork, their richly marbled grain giving the look of travertine. The cork capsule rises inside a wooden lift shaft too, through seven floors of work space, each office exuding the smell of an alpine chalet.
“We’re getting a really clear understanding of the biophilic benefits of natural environments, beyond the carbon savings,” says Andrew Waugh of Waugh Thistleton, the architects behind the project. “People sleep better in timber homes, study better in timber schools, heal faster in timber hospitals and have less stress in timber offices.”
Waugh is one of the UK’s most vocal advocates for mass timber construction, having worked with wood for the last 20 years. His practice’s nine-storey Murray Grove housing scheme in Hackney, completed in 2009, was the first tall urban housing project in the world to be constructed entirely from prefabricated solid timber. Not that the client wanted to shout about it.
“They said: ‘You can build it in timber, as long as you don’t tell anyone,’” Waugh recalls. Their concern was about public perception. To most people, wood is something you throw on the fire, not build towers from. “But have you ever noticed,” Waugh asks, “that when you have a campfire, the big log will still be there the next morning? The outside is charred, but it hasn’t burned through.”
Such is the principle behind structural mass timber. With sheets of wood laminated together, like supersized plywood, it is designed with “sacrificial” outer layers that would char in the event of a fire, protecting the inner structural integrity. Waugh shows me a historic photograph of a fire-ravaged building, where the steel beams have melted and collapsed, drooping like spaghetti over a charred wooden beam that remains intact and structurally sound.
Timber technology has come a long way since then, and even since the days of Murray Grove. Along with walls and floor slabs of cross-laminated timber (CLT), the Black & White building’s structural frame of columns and beams is made from beech laminated veneer lumber (LVL), used on this scale in London for the first time. The material is created by peeling a tree (essentially putting the trunks on a giant spiralizer) rather than cutting them into planks, and gluing the thin layers together, thereby reducing waste and creating tougher, more slender components – “as strong as steel but 20% of the weight and a fraction of the carbon,” says Waugh.
When I first visited the Shoreditch construction site in the summer of 2021 it was an astonishing scene, with gigantic LVL columns and beams being effortlessly bolted into place like a supersized balsa wood model (allowing for disassembly and reuse in future). But the most unusual thing was the sound – or lack of it. Where building sites are often cacophonous places of drilling and hammering, amid clouds of toxic dust, this was a serene, silent assembly line. The site manager was beaming: “We’ve had compliments from the neighbours about how quiet it is,” he told me. “The scaffolding was probably the noisiest part.”
The project took around six months less to build and involved 80% fewer truck deliveries than an equivalent concrete building, reducing congestion and pollution on the city’s streets, while not a single skip went to landfill. “We drew every component on the computer and our files went straight through to be cut in the factory,” says Waugh, his eyes wide with evangelical glee. “Every piece of timber is engineered for its exact purpose, so there’s no waste. The modernists talked about ‘truth to materials’, but then they clad everything. Here, everything you see has a structural purpose – this is proper, hard-arsed modernism.”
The beauty of building with wood is that it is truly renewable, and actively sequesters carbon from the atmosphere as it grows.The trees used for the project were grown in vast certified forests in Austria and Germany, where five trees were planted for every one cut down.
The UK structural timber industry, however, is sadly lacking: most of our trees are simply burned to fuel power plants. “We’ve got our subsidies completely the wrong way around,” says Waugh. “If you cut down a tree and burn it, it is subsidised. If you put it in a building, it’s not.” A recent report found that the UK government subsidises logging for bioenergy by almost £2bn a year.
Building regulations and insurers’ risk aversion aren’t helping either. For years, the UK was one of the world leaders in structural mass timber, even if we didn’t grow it. “In 2018, we represented 15% of the global CLT market,” says Waugh. “Now we represent less than 1%.”
The reason? The backlash after the Grenfell Tower fire – even though there was no structural timber in sight. Regulations introduced in 2018 banned the use of combustible materials in external walls of buildings over 18 metres, while the mayor of London went even further, forbidding its use in the walls of any residential development wanting eligibility for affordable housing funds, regardless of height.
“Our office had about 2,000 homes for housing associations and local authorities under way,” says Waugh, “which were all cancelled overnight.” Most are now being built in concrete instead. “We have a concrete industry that behaves like the tobacco industry did in the 1990s,” he says, “trying to prove that smoking is healthy. The idea of ‘green concrete’ is ridiculous.” Cement manufacturing accounts for at least 8% of global carbon emissions, and cement alternatives are a byproduct of equally polluting industries.
While other countries forge ahead with residential timber buildings, in the UK it is the office market that looks likely to lead the way, being unhampered by the same rules as homes. In the commercial sector, the overwhelming incentive for low-carbon construction is not being driven by policy but by demand from tenants and funders.
“The pressure is coming from occupiers and investors,” says Green. “Just being in our building ticks their ESG reporting box.” He is referring to the environmental, social and governance criteria, which have become a major priority for companies and investment funds around the world that are looking to measure value beyond financial performance alone.
In 2017, the Office Group was acquired by Blackstone, the world’s biggest ever corporate landlord, which manages $951bn of assets on behalf of pension funds and institutions – and which UN advisers have accused of contributing to the global housing crisis, a claim the company vehemently denies. With environmental perception front of mind, Blackstone proudly featured the Black & White building on the cover of a recent brochure, trumpeting its green credentials to its clients.
“If you had asked us 10 years ago, what is going to drive sustainability, I would have assumed it would be politicians and legislation,” says Waugh. “But it’s not. It’s money. ESG is the new gamechanger for sustainability, and it’s ultimately being driven by small-time investors – the school teachers, postmen and nurses who are looking to green pension funds for their futures.” As ever in the development industry, form follows finance. Only this time, it’s keen to be seen to be green.
• This article was amended on 31 January 2023. An earlier version referred to the UN, rather than UN advisers, as having accused Blackstone of contributing to the global housing crisis.