Why the Same Concrete Is Loved and Hated

Concrete has exactly the weakness stone has. It is strong when squeezed and weak when stretched, which means that on its own it can do arches and walls and nothing much else.

Put steel bars where the stretching happens and the problem disappears. The concrete takes the compression, the reinforcement takes the tension, and together they do what neither can: span flat, cantilever out into the air, hold a roof up without a vault, carry a slab on thin columns with no wall at all.

This is why twentieth-century buildings look the way they do. Not because somebody decided walls were old-fashioned, but because reinforced concrete made the wall structurally optional for the first time in history.

Béton brut means raw concrete: left as the mould formed it, with the grain and the joints of the timber shuttering printed into the surface and the tie-holes visible. Le Corbusier used it at the Unité d'Habitation in Marseille, finished in 1952, and the term was later shortened and anglicised into brutalism, which has caused eighty years of confusion by sounding like an insult.

The attraction was partly economic and partly moral. Economically, raw concrete skips the finishing trades entirely: no render, no cladding, no plaster, which in a continent short of everything after 1945 meant housing built at a speed and price nothing else could match. Morally, the surface tells the truth. You can see how the building was made, where each pour stopped, how the formwork was assembled. Nothing is hidden behind a skin.

Both of those were real, and both had a cost that was not obvious at the time.

Raw concrete is a permanent record of the workmanship. A badly aligned shutter, a pour that segregated, a bar set too close to the surface: all of it is visible for the life of the building and none of it can be covered up afterwards. Brick forgives, render forgives, cladding forgives. Béton brut does not.

And raw concrete punishes neglect faster and more visibly than any traditional material. Water tracks down the face and stains it. Where the cover over the reinforcement is thin, moisture reaches the steel, the steel rusts, rust occupies more volume than steel, and the concrete spalls off in sheets. A brick terrace left alone for thirty years looks old. A concrete slab left alone for thirty years looks condemned.

Which brings us to the verdict, and to the strangest fact about these buildings: the same architecture is being protected and demolished simultaneously.

The Barbican is listed and sought after. Trellick Tower is listed and its flats sell well. Robin Hood Gardens, by the same generation of architects and in the same material, was demolished. Pruitt-Igoe in St Louis was dynamited in 1972 and became the standard illustration of modernist failure in a hundred books.

If buildings of the same date, material and detailing are reaching opposite verdicts, the verdict is not tracking the architecture.

So before accepting that any of these estates failed, ask three questions.

What happened to its maintenance budget after it opened? Many were costed on an assumption of continuous upkeep, and in Britain the funds for that were cut repeatedly from the late 1970s onward.

Who was housed there, and on what terms? Pruitt-Igoe was racially segregated in practice, funded by a formula that paid for construction and not for management, and losing tenants to suburbs its residents were excluded from. Those are not architectural facts.

And would a brick building on the same site, with the same tenants and the same funding, have fared differently?

Some of these buildings were genuinely bad: badly planned, badly lit, hostile to walk through at night, and the people who criticised them at the time were often right. The deck-access scheme that becomes a corridor nobody can see into is a design failure and no amount of context rescues it.

But a good many were ordinary buildings subjected to an experiment in neglect, and the architecture took the blame because the architecture is the part you can photograph.