The Unité d’habitation in Marseille, opened in 1952, remains its ultimate symbol. The flats offered a very high standard of comfort for the time: central heating, ventilation, double glazing, loggias and sunshades designed specifically to let in light in winter whilst filtering it out in summer.
The problem is that the climate of the 21st century is no longer the one for which these buildings were designed.
In Firminy, one of the Unités d’habitation designed by Le Corbusier, some residents have recently described a daily life that is far from ‘radiant’ during heatwaves: flats where temperatures can reach nearly 40 °C. Concrete, large glazed surfaces, sun exposure and the sometimes limited scope for modifying the façades can turn certain homes into veritable heat traps.
The irony is cruel: Le Corbusier had, in fact, devoted a great deal of effort to controlling the sun’s rays. The sunshade is one of the iconic features of his architecture. In some of his projects, he also gave careful consideration to natural air circulation, orientation and measures to protect occupants from solar radiation.
However, not all Unité d’habitation projects were built with the same resources. In Firminy, the Le Corbusier Foundation itself points out that the financial constraints of the social housing scheme resulted in thermal and acoustic insulation that did not meet the architect’s standards.
We must therefore be wary of making overly simplistic judgements against Le Corbusier. The real issue is perhaps more interesting: what should be done with revolutionary architecture that has become heritage when climatic conditions change radically?
For protecting a monument and protecting those who live within it can now come into conflict.
Installing additional sunshades, replacing glazing, carrying out work on the façades or modifying certain ventilation systems becomes much more complicated when the building has significant heritage value. Architecture must then strike a balance between two imperatives: preserving the building and making the living conditions bearable.
However, research specifically focused on the climate adaptation of Le Corbusier’s buildings shows that there are possible solutions. Sun protection, suitable glazing and, above all, natural ventilation can significantly reduce summer discomfort. But some conventional insulation solutions can also have an adverse effect: they trap more heat in summer when poorly designed.
This is probably where the key question raised by Le Corbusier’s legacy lies.
His architecture was an architecture of progress. To freeze it in time in the name of conservation would be almost at odds with the experimental spirit that gave rise to it.
The Cité Radieuse was a machine for living in.
A machine, normally, requires maintenance, adjustment and adaptation.
At a time when heatwaves in France are becoming more intense, certain 20th-century masterpieces will have to learn to adapt to the 21st century. Otherwise, behind their façades, admired by tourists and architecture enthusiasts, their residents are likely to continue discovering a far less photogenic reality:
the Cité Radieuse transformed, for a few weeks each year, into a concrete kettle.
