Herzog & de Meuron’s climate U-turn

“Dear David,” Jacques Herzog wrote to David Chipperfield in 2020, when the British architect was serving as guest editor of Domus. (The design journal has in recent years surrendered editorial control to a parade of celebrity architects, with Bjarke Ingels the latest to be tapped, but that’s a story for another Punch List.) “You ask me what we architects should do about the unmistakably impending environmental catastrophe…. Dear David, the answer is: nothing. Or do you know of any moment in the history of architecture in which an architect contributed to the decisive issues of society?”

Well, I think it’s fair to say that things have changed in Basel. Herzog and Pierre de Meuron, childhood friends who founded their architecture office in that Swiss city in 1978, have recently established a sustainability team within the firm, led by Alexander Franz, and made research into hyper-efficient buildings a top priority. As Herzog said recently, presumably while wearing a Prada hair shirt, “Sustainability should be at the forefront of everything we produce—indeed, everything we do.”

Far more significant than this philosophical 180—which mostly suggests the office’s savvy in understanding where commissions come from now and may come from in the future—the firm has just completed a masterful project in the Switzerland Innovation Park in Allschwil, very close to Basel, that demonstrates what the new commitment might yield architecturally. Even if the building is in many ways a demonstration project, bankrolled by a generous and ambitious client and as a result immune to certain market pressures, it also provides some clues about where much-hyped mass-timber construction, in particular, might go from here.

Called Hortus, an acronym for House of Research, Technology, Utopia, and Sustainability, it’s a five-story modular office block that sits alongside two earlier buildings by Herzog & de Meuron, both of concrete, and a parking garage. These adjacencies are meaningful; we’ll come back to them.

Hortus doesn’t look like much from the outside. (I was going to say it’s nothing to write home about, but here I am writing home about it.) When I met up with Franz for a tour of the building earlier this week, the white automated blinds were drawn against the morning sun across the entirety of the front façade. Along with the design’s horizontal bands of dark photovoltaic panels, this created a simple, even banal black-and-white pattern. The building’s silhouette, wide and low-slung with a hipped roof, is also fairly nondescript. Given Herzog & de Meuron’s long history of wrapping projects in succession of eye-catching skins, each more daring than the last, these qualities struck me as perhaps a frank concession to the pragmatics of sustainable building.

But as soon as you step toward the passageway slotted into the middle of the façade, you begin to notice the very high level at which the architects are operating here. A grid of columns in ash wood, chamfered at the edges, gives rhythm to the space, which serves as a sort of open-air lobby. Ahead of you is a courtyard planted with a garden by Piet Oudolf in what, Franz told me, might be among the final projects of the 80-year-old Dutch plant-whisperer’s career. Covering a tank that collects rainwater, for use in irrigation and flushing toilets, the garden is lined with climbing vines that will shade the office interiors in summer. 

It also offers a glimpse at the unusual way the building meets the ground. In order to reduce concrete use to an absolute minimum, Hortus has no basement. (All the HVAC and other mechanical equipment is stashed away on the ground floor. A geothermal system provides heating and cooling.) The building, made almost entirely of mass-timber framing above ground, touches down on a grid of more than 200 concrete piers—concrete feet, really—that extend just six feet into the earth. As you stand in the garden, feeling the pleasant chimney effect of air drawn into the passageway and up through the courtyard, you can look beneath the timber veranda that rings the garden and see how the base of the building comes together—how it seems to float atop its wooden platform.

I found the directness of this feature disarming, the architectural equivalent of what’s known in Las Vegas as “clearing the hands,” when a blackjack dealer pulls back his cuffs and shakes his wrists before he leaves the table, to make clear that he hasn’t palmed any chips or hidden a card up his sleeve. I was also reminded here and elsewhere in the building of Japanese joinery—as well as, to be more specific, the way American Craftsman architects like Greene and Greene interpreted Japanese joinery in many of their residential designs more than a century ago.

Inside, past the ground-floor gym and café, there is a wide passageway with co-working tables on one side (these are open to the public) and tall windows with views of the garden on the other. If you stop here and look up at the ceiling, you can get a direct sense of another detail that makes this project remarkable. Exposed rammed earth fills subtly vaulted channels across the entire ceiling. More than three-quarters of this soil was pulled directly from the building site.

The ceiling has the same load-bearing capacity as the concrete slabs Herzog & de Meuron used in the two neighboring buildings, Franz said, but with just 10% of the carbon footprint. In addition to providing enough thermal mass to help keep the building cool in summer and warm in winter, and meet the required fire codes, the soil (piled about five inches high, with plywood above that) provides sound insulation between floors.

“About forty percent of the overall carbon footprint of a building lies in the ceiling,” Franz told me. In terms of sustainability, “This was our lever.”

There’s also something remarkable about taking the soil excavated during construction, lifting it into the air, using it to finish the slabs between floors, and leaving it exposed above visitors’ heads. The rammed earth becomes an emblem of this huge global firm’s return, at least in this one case study of a project, to the hyperlocal. It also gives the building a particular color palette and material sensibility—a sort of architectural equivalent of winemaking’s terroir, and something Herzog & de Meuron are trying on other projects (an echo, in terms of connection to place, of the gabion walls that ring the firm’s 1998 Dominus Winery). “We’re working on a winery in Bordeaux now,” Franz said, “and the soil there is yellow.”

I told Franz that this reminded me of the experimental technique Frank Lloyd Wright used in his textile-block houses in Los Angeles, in the early 1920s, using a concrete mixture made in part from soil from the building sites. Hortus probably will leak less.

A little further along the ground-floor hallway is a restaurant serving the building’s tenants as well as those from elsewhere in the Innovation Park. (On the day I visited, I saw employees from nearby offices walking into Hortus for lunch, carrying their own ceramic plates and bowls.) The chairs are Vitra’s familiar Basel model, by Jasper Morrison, but every one of them is second-hand—they were thrifted, essentially, and then painted a uniform white. The Aalto stools along the hallway are also second-hand.

There are twisting stairs in raw steel leading up from the ground floor. The stair cores are the only place in the project where steel is used in any significant amount and also among the design’s few virtuosic, as opposed to virtuous, touches. (The design of every project the firm undertakes is still credited, officially, to Jacques and Pierre; Stefan Marbach was partner in charge on this one. The engineers, ZPF, also played a crucial role.) The office floors have a footprint narrow enough to flood them with natural light from windows both along the perimeter and facing the courtyard.

The windows themselves pivot a full 90 degrees thanks to a hinge midway up the frame, for maximum natural ventilation when open (borrowing an old technique that Julia Morgan, as it happens, used in two big picture windows in the 1920 Berkeley house where I grew up). On the upper floors, the way the building shades and cools itself allowed the architects to use double instead of triple glazing, which is otherwise de rigeur in Switzerland, saving on cost, weight, and carbon footprint.

The columns through the middle of the space are beech. Along the perimeter of each office floor, where they have less of a structural role to play, they are instead spruce, a softwood that grows twice as quickly. “The visual difference between the two woods is subtle, and we don’t mind it,” Franz told me. It’s hard to imagine a Herzog & de Meuron architect saying something like that—admitting to, even embracing, a material inconsistency—a decade ago. With the exception of oak flooring, nearly all the wood in the building comes from forests in St. Gallen, less than 100 miles from the site.

As on the ground floor, the ceiling on the office levels is a revelation. Here the slender cylindrical lights, hanging horizontally like so many transparent flutes, are a custom design in glass and metal—no plastic. They have built-in sensors on one end that monitor temperature, humidity, and air quality, triggering the heating and cooling system when needed. This combination of light and sensor is among the many ways the architects have kept the ceiling almost magically free of clutter.

In its basic structural logic, Hortus suggests that mass-timber construction has finally come of age. In many mass-timber projects I’ve seen recently, the use of engineered wood is either compromised by relying on a hybrid system, usually featuring a steel frame into which timber is laid—this has been the case in Los Angeles, for example—or becomes a kind of fetish, with the architects overplaying their hand and covering every last interior expanse with wood. Here the architects rely on a kind of render-unto-Caesar logic, with timber employed everywhere it makes structural and pragmatic sense and avoided everywhere else. (When the blinds are drawn along the exterior, the building doesn’t read immediately, from afar, as a timber project.) I imagine architects working on mass-timber designs for other firms will be studying it closely.

Once I stepped back outside, I had a chance to look more carefully at the photovoltaic panels, which wrap each side of the building, in four horizontal bands, as well as cladding the hipped roof. The simple color scheme works as a kind of diagram, with the black bands marking the areas where the building wants to absorb sun and the white ones where it wants to block it. “This is the first Herzog & de Meuron building where we used PVs as an integral part of the architecture, instead of hiding them away on the roof,” Franz told me. The ratio of space allocated to PVs (5,000 square meters) to usable floor space (12,000) is very high, allowing the building to produce about 40 percent more energy than it consumes.

“One of the tasks was to create a building that amortizes its energy footprint within one generation,” Franz said. “That was written into the contract.”

There is nothing groundbreaking about any of these choices in isolation, of course, although the architects’ collaboration with ZPF has made the quantification of the building’s sustainability goals unusually rigorous. The nearness of the adjacent buildings, especially the parking structure, mean that certain carbon-intense programmatic elements that might have needed to be squeezed into a standalone office building, such as below-ground parking, could be outsourced to the rest of the campus. The client, the Swiss real-estate company Senn, was willing to take financial and other risks in support of an ambitious energy and material strategy, and of its own marketing. So best to think of this as a demonstration project for everyone involved.

You could certainly fault Herzog & de Meuron for failing to see the light on the climate crisis for so long, and for being—as Jacques Herzog was in the Domus letter—so cocksure about that blind spot. You could point to the ungodly amount of concrete and steel the firm used in earlier projects, such as the 1111 Lincoln Road parking structure in Miami Beach or the “bird’s nest” National Stadium in Beijing. You might reasonably conclude that the firm’s latest pivot smacks of opportunism, or that it reflects a firm that has been in so many other ways a trailblazer finding itself, when it comes to climate, embarrassingly behind the pack. 

You might also say, if you still believe in the notion of the zeitgeist, the idea that architecture should reflect the spirit of the age, that what Hortus suggests about the spirit of our age is that it’s anxious and somewhat pinched in its ambitions, not to mention eager to find comfort in certain premodern design strategies.

I wouldn’t argue with you about any of that. The acronym Hortus may include a U for Utopia, but this is a decidedly modest and well-behaved version of paradise—a very Swiss version, in other words, where you carry your own plates and bowls to the restaurant and wash them yourself before you leave. And yet the twin demands of carbon-consciousness and spatial quality are resolved here with extraordinary deftness. The building is only the latest sign that among the world’s largest architecture firms, Herzog & de Meuron is consistently reaching a level of quality and rigor that few of its competitors, if any, can match.

There’s an unusually well-considered marriage throughout Hortus of the high-tech and the low, the automated and hand-crafted, the thrifted and bespoke. The building is smart where it needs to be and dumb where it needs to be; heavy where it needs to be, and light; obsessive about detailing but also, where it’s necessary for reasons of energy-efficiency and carbon footprint, willing to compromise the purity of some of those details. The view beneath the building that you can glimpse while standing in the garden is a marvel, and all the more striking for its frankness. This is true, in fact, for the project as a whole: though it required no shortage of expertise, its elegance flows directly from its plainspokenness.

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