The Dignity of Concrete: Why the Future of Cities Lies in Reuse, Not Demolition

I often walk through Brussels, especially in the evening, when the rush-hour crowds begin to thin out and the city reveals itself for what it is: a vast, disorderly palimpsest of stone, concrete, and brick. If you look at the skyline from Place Poelaert, or walk between the office buildings of the European Quarter and the old houses in my neighborhood of Ixelles, one thing becomes immediately apparent: the city is not standing still. But the way it is changing is undergoing a profound transformation.

Until not long ago, the standard response to an obsolete building was almost always the same: demolition. There was this peculiar belief that tearing down a concrete block from the 1970s and replacing it with a gleaming glass tower—perhaps covered with plants on its balconies—constituted ecological progress. They called it renewal. Yet every time I saw a demolition site in the city center, with trucks loaded with rubble clogging the streets, I could not help thinking about how much energy we were literally throwing away.

That is really the point: embodied energy. Or what is commonly referred to today as embodied carbon.

Behind this technical term, which is now constantly invoked in architecture schools and professional conferences, lies a very tangible reality. The concrete, steel, and bricks that make up the city's structural framework already carry an enormous environmental cost, paid decades ago through the emissions generated during their production and transportation. When we demolish a building, we erase that value and start over from scratch, generating more CO₂ through excavation, manufacturing, transport, and construction. Preserving the structural frame and focusing instead on the envelope—the building's skin—may be the last truly radical act of sustainability available to us.

In practice, however, things are never that straightforward. There is an internal contradiction that I often encounter when evaluating or discussing these projects.

Take a two local examples here in Brussels: the conversion of the World Trade Center towers, the Zinneke project and the Brunfaut Tower, or the many large-scale refurbishment projects underway in the Northern District. On paper, the strategy is virtuous. The concrete skeleton is retained, the old inefficient façade is removed, and a new high-performance envelope is installed. But once you step onto these construction sites, you begin to understand the complexity of the undertaking. Adapting a structural frame designed fifty years ago to contemporary standards for fire safety, acoustic insulation, and usable floor heights is an extraordinary feat of architectural surgery. At times, one wonders whether the economic and technical effort outweighs the benefits, or whether too many compromises are being made in the quality of interior spaces simply to preserve that concrete frame.

It is a legitimate question. Architecture is not a mathematical equation in which adding up kilograms of CO₂ saved automatically produces a good project.

There is also an issue related to the material itself, to its skin. In many cases, making an old building thermally efficient means wrapping it in layers of synthetic insulation, then covering them with render or lightweight cladding panels. The building becomes efficient, consuming less energy for heating, but it loses its tactile presence. It becomes a mute object, slightly artificial. The embodied carbon is preserved, but the visual memory and character of that fragment of the city risk being lost. In Brussels, where the urban fabric is already fragmented and largely devoid of any rigid coherence, this kind of "cosmetic" intervention risks making everything look the same.

And yet, I do not believe there is a viable alternative. We can no longer afford the luxury of tabula rasa. The challenge is no longer to design the perfect form on a blank sheet of paper, but to learn how to read what already exists, accepting its limitations and imperfections.

Every day I watch a construction site next to my home. A former office building is being converted into housing. The workers have stripped the concrete columns of this anonymous and, frankly, rather unattractive office block down to their bare structure. There was nothing historically significant about the building, no remarkable ornamentation or architectural distinction. And yet, once freed from its plasterboard partitions and suspended ceilings, that structural grid revealed a certain dignity, a raw strength of its own. It spoke of the labor of those who had built it, of the passage of time, of the almost eternal power of concrete.

Perhaps radical sustainability is also this: stopping the endless pursuit of novelty and rediscovering the value of maintenance, adaptation, and making do with what already exists. It is a less spectacular approach, one that requires more patience and perhaps more humility. Yet it seems to be the only way to give our cities a meaningful future without continuing to consume the planet one concrete block at a time.

#SustainableArchitecture #UrbanRegeneration #EmbodiedCarbon #Brussels #ConcreteReuse