In April 2023, many New Yorkers learned of the renovation of the Brussels World Trade Center (WTC), spearheaded by Belgian office 51N4E, in a lecture hosted by The Architectural League of New York at The Cooper Union. Titled “How to Not Demolish a Building,” the lecture (and a book of the same title) outlined 51N4E’s half-decade involvement in the enormous project to modernize two obsolete office towers into a mixed-use complex of luxury apartments, a hotel, bars, restaurants, and more office space. Though presenters Olivier Cavens and Dieter Leyssen offered a litany of diagrams, spreadsheets, renderings, and photographs reflecting on years of research and outreach, many in attendance noticed a disconnect between the language used to describe the aspirations of the project and what was onscreen. At a dinner following the event, another architect broke the ice by posing an obvious question: “So did you demolish the building or not?”
The confusion stemmed from a tenuous promise to preserve as much of the original building as possible in the interest of reducing construction waste. 51N4E’s initial, competition-winning design proposed to limit most new construction to a new volume of double-height floors delicately placed between the existing twin-towered structure, offering additional leasable area and a means of delivering infrastructural upgrades to the building. This kind of “if it ain’t broke, don’t fix it” approach has been employed successfully by firms like Lacaton & Vassal, celebrated for designing careful additions around existing housing blocks that allow residents to stay in place. 51N4E sees further ecological value in designing its addition to permit multiple uses over time, theorizing that adaptability will allow the building to survive future market fluctuations and thus extend the structure’s lifespan. At the lecture, 51N4E criticized other architects in the competition who proposed demolishing the WTC buildings outright.
But shortly after 51N4E was selected to design the complex, it became clear the existing architecture could not be reconciled with the client’s requirements. Instead of aborting the project, as collaborating material-recycling consultant Rotor at one point suggested, 51N4E moved the goalposts, adjusting its definition of preservation to include any demolished material that could be recycled while relying on the metric of building weight to argue that 60 percent of the original material was retained. Work then focused on cataloguing materials slated for removal and either finding places for them in the new project or on the marketplace. Finally, with a touch of absurdity, 51N4E designed a wholly new facade to resemble the old in a way that suggests conceptual purity was maintained.
While the design decisions behind the realization of ZIN (as the completed project is named, short for zinnekes: a Flemish slang demonym for Brusseleirs) may be practical and rigorous, the site was infamous in Brussels long before 51N4E’s involvement. The original WTC project was the centerpiece of a state-developer-architect-ideated masterplan circa 1976 to “Manhattanize” the Northern Quarter of Brussels into a new commercial district reflective of Belgium’s emerging centrality to global finance. Doing so required razing the entire neighborhood, displacing as many as 11,000 working-class and immigrant residents. But the desired financial tenants never came (the banks opted to build their own towers in tonier neighborhoods), and the site had lain fallow for decades following. A friend in Belgium reminded me, “Brusseleirs are quite used to huge, failed projects,” to the extent that the Flems have a word to describe the cycles of large-scale destruction resulting from haphazard planning: verbusseling, or “Brusselization.”
The WTC would reshape both the physical and political geographies of the city and set the terms for its future rehabilitation. In response to mass evictions, land seizures, and broken promises for new housing, residents across the city organized into a constellation of community groups that were able to leverage the city government to reform the approvals processes for large projects. Balancing client demands against public scrutiny and civic review processes, 51N4E (in collaboration with an alphabet soup of design consultants) hosted a series of local workshops, neighborhood meetings, and public-facing spectacles in the empty buildings. 51N4E would go on to present the merits of these events, but many community groups regretted their involvement or abstained altogether. Further, the community of refugees who came to live in or around the WTC buildings was systematically excluded from participation and eventually forcefully removed from the neighborhood prior to construction.
While aware of the numerous crises that flow through the site, 51N4E has the tendency to reduce its positions to quips like “Deal With the Trauma,” when organizing presentations of its work on the project. While this kind of Silicon Valley–esque sloganeering could be forgiven as an attempt to distill complex goals to the public, it can also have the effect of obscuring whether or not the public groups that participated in this project had any agency in its outcome. Given that the original buildings were built by removing a busy neighborhood and its residents, it’s not a stretch to expect that “dealing with the trauma” would involve some reparative concession to this still-living community, but the designers clarify that trauma narrowly describes the formal issue of the monolithic buildings, cured by inserting a “mixity” of luxury uses.
If the core injustice of the original WTC scheme was, as 51N4E put it, “wiping out a whole part of the city for the ‘new,’” then the consequences of building anew again for the sake of adaptability must be critiqued. The decision to demolish the old buildings stems in part from the need to incorporate a new plenum floor that facilitates converting the building from one use to another. Once the Flemish government’s lease (and the requirement to include housing in the complex) expires, the owner could choose to evict its residential tenants and convert the building to more profitable commercial use. In this way, the implementation of new technology promises that displacement of people can continue with greater efficiency as it will no longer require the physical complications and costs of demolition.
The framework 51N4E offers for recycling is also disconnected from the realities of architectural production’s cycles of extraction and waste. Recycling is not one-to-one—glass does not get reused as glass, concrete does not get reused as concrete—and every stage of recycling a material downgrades it. An old concrete building that is demolished and replaced with a new concrete building will still need new concrete along with the attendant labor to mine the aggregate, mix and transport the cement, assemble the formwork, furnish steel rebar, and pour the material in place. This conception of recycling upholds an existing class order; it presupposes that material extraction by the corporate class is both inevitable and justified because its trash is valuable to lower-class builders.
Ultimately, ZIN is not really any better or worse than a dozen other new towers in Brussels. It is likely that the building would escape greater controversy and critique were it not for a fusillade of publicity taking the form of books, lectures, essays, exhibitions, research projects, and academic studios, which have the cumulative effect of both inflating the importance of ZIN while diminishing the rigorous design work undertaken to realize the building. The enormous volume of positivistic claims made by 51N4E requires rigorous rebuttal, deflecting energy that could go into critiquing the technical aspects of the building itself or doing actual social organizing.
Responding to a mild review of the project by Christophe van Gerrewey in The Architectural Review, 51N4E principal Freek Persyn took to Instagram to rebut: “I agree with the observation that what we do in the North Quarter raises many questions. That is why it feels strange that the effort of publishing about these questions and doubts is in itself questioned. As if we try to prove something, while in my mind we just try to share what is happening.” Persyn wants it every way: to do the project, to not be responsible for the decisions made in realizing the project, and to control the terms by which the project is critiqued.
While new software and technologies infringe on the specialized technical services that compose architectural billing, 51N4E is experimenting with an expansive new form of practice that absorbs critical language in an effort to undermine it. As van Gerrewey noted, “It is…indicative of the pressure on architects to work in a way that appears to be ‘sustainable’ while clients often simply want a brand-new building as quickly and efficiently as possible.” Whether the project actually fulfills a stated goal of social equity or carbon neutrality is irrelevant so long as the pool of prospective clients believes it and the project meets its bottom line.
Brad Isnard is a designer based in New York.
