For much of the twentieth century, Western architecture treated raw earth as a material "waiting to be replaced" — a poor technology, tolerated only where cement hadn't yet arrived. Francis Kéré and Anna Heringer belong to a generation of architects who overturned that hierarchy, not out of nostalgia but through precise technical and social calculation: both built their international reputations — Kéré won the Pritzker Prize in 2022, the first African architect to receive it — by showing that raw earth, if designed with rigour, can be the smartest material available in a given context, not the fallback of those who can't afford anything else.
Francis Kéré: building the community alongside the building
The project that made Kéré internationally known, the Gando primary school in his home village in Burkina Faso, uses locally produced compressed clay bricks, structurally stabilised and reinforced, covered by a corrugated metal roof raised on a secondary structure that creates a ventilated air gap — a decisive technical detail in a hot climate, because it keeps the overheated roof away from the clay ceiling below, which thereby retains a cool thermal inertia by exploiting the material's mass. For Kéré, choosing local earth was never a purely aesthetic or symbolic decision: his European technical training (Kéré came to Germany as an apprentice carpenter and later graduated in architecture from TU Berlin) let him calculate and reinforce a local material with modern engineering criteria, while also structuring the building site as a professional training process for the village's residents, who learn construction skills usable well beyond the single project. It's a model in which the building and the community that builds it are formed by the same process — here, raw earth isn't just a material, it's the instrument of an explicit social project.
The Gando school grew out of an almost personal initiative. While still a student in Berlin, in the late 1990s Kéré founded with friends and colleagues an association to raise the funds needed to build a school in his village, where as a child he had had to leave home to study. The first building, completed in 2001, received the Aga Khan Award for Architecture in 2004, one of the most important awards for architecture in developing countries. In the following years the complex grew with teachers' housing, an extension of the school and a library, into whose clay ceiling Kéré set cut terracotta pots made by the village women: they became small rooflights and ventilation openings, turning a traditional household object into an architectural element.
With international success Kéré's work expanded to other materials and scales without losing the same logic. At the Lycée Schorge in Koudougou (2016) the walls are of laterite blocks, a reddish stone that is easy to cut when freshly quarried and hardens in the air, and the spaces are wrapped in screens of eucalyptus poles that give shade and create places to linger outside the classrooms. In 2017 Kéré designed the Serpentine Gallery's summer pavilion in London, a large canopy inspired by the crown of the tree under which village communities gather. After the 2014 popular uprising in Burkina Faso he also designed a new National Assembly building, conceived as a stepped hill open to citizens: a project that has remained on paper because of the country's political events, but which shows how for him architecture is inseparable from public life.
Anna Heringer: mud trodden by animals
The METI school in Rudrapur, Bangladesh, designed by Anna Heringer with engineer Eike Roswag, uses a combination of raw earth and bamboo — the same two materials the region's local tradition had always used separately, brought together here in a hybrid structural system: the ground floor is built with massive cob walls (earth mixed with straw, with no formwork or bricks), while the first floor is a lightweight bamboo structure. The cob mix for the walls was traditionally prepared by walking oxen and cows in a circle over the mixture of earth and water — a manual-animal working method that replaces mechanical energy with extremely low-impact labour — and one that, in Heringer's project, was deliberately kept, not replaced with faster industrial techniques borrowed from the West.
The choice had a second effect, perhaps more important than the strictly architectural one: the building site employed and trained local village labour in improved earth-and-bamboo construction techniques, with the explicit aim of transferring skills applicable to improving the area's informal housing, not just to building this one school. As with Kéré, architecture becomes the pretext for a transfer of technical skill that outlives the project itself.
Heringer's path also has personal roots. As a young woman she spent a year in Bangladesh with a local non-governmental organisation, and there developed the idea that architecture could improve living conditions in rural areas without importing foreign models. The METI school, designed as her graduation thesis at the University of Linz and built in 2005–2006, received the Aga Khan Award in 2007. In the same village followed a vocational school for electricians, DESI, and a project of two-storey rural houses, HOMEmade, built with the same materials to show that earth and bamboo can provide healthier, more durable dwellings without raising costs.
Her most recent and perhaps most mature project is Anandaloy (2020), a building that houses on the ground floor a centre for people with disabilities and on the upper floor a textile workshop run by women from the village. To ensure access for wheelchair users, Heringer did not add a lift, which would need electricity and maintenance, but wrapped the building in a long, curving earthen ramp, which also became the liveliest space in the building, where children play and people meet. The technical solution to the problem of accessibility thus becomes the very image of the architecture. Heringer also holds an honorary UNESCO chair in earthen architecture and teaches at several European universities.
Returning to the METI school, a few details explain why it works. The earth walls rest on a brick foundation with a layer that blocks rising damp, the most delicate point of any earth building in a country subject to monsoon rains and floods. The roof overhangs generously to protect the walls from driving rain. On the ground floor, the thickness of the cob walls is hollowed into niches and small rounded caves, intimate spaces where children can read, play or withdraw: the mass of the material becomes furniture. On the upper floor, the bamboo structure is light and open and lets the breeze through. Every choice responds to climate and use, and each material is used where it works best: earth where mass and protection are needed, bamboo where lightness and ventilation are needed.
What they share: technical rigour, not an aesthetic of poverty
What makes both architects relevant to a technical, not merely aesthetic, reading of contemporary raw earth is their shared refusal to treat the local material as a constraint to be passively accepted. Both Kéré and Heringer apply formal engineering skills — structural calculation, climate detailing, reinforcement systems — to a material that vernacular tradition had already optimised empirically over centuries, but without the ability to verify it with the tools of modern engineering. The result isn't a return to the past but a hybridisation: local techniques validated by contemporary calculation, in a process that restores technical dignity to a material industrialised architecture had dismissed as primitive.
The problem of perception
Anyone working with earth in these contexts meets an obstacle that has nothing technical about it. In many African and Asian villages the mud house is associated with poverty, while concrete and corrugated iron are the visible signs of progress and prosperity. Proposing earth can seem, to the residents, an invitation to stay poor. Kéré and Heringer tackled this problem not with speeches but with the quality of their buildings: schools cooler than those built of concrete blocks, brighter, built with evident care and recognised internationally. It is quality, not the rhetoric of sustainability, that convinces a community that a local material can be modern.
Critical questions are not lacking. Many of these projects depend on international funding and on the charismatic figure of the architect, and there is a risk that they remain exemplary exceptions rather than changing ordinary building practices. Both are aware of this, which is why they insist on training local builders: the real result is not the single award-winning school, but the number of people who, having built it, know how to build their own houses better. Measuring this effect is difficult, but it is on this ground that their work will be judged in the long run.
And in Europe?
The same technical seriousness is bringing earth back into European architecture too. The main reference is the Austrian Martin Rauch, a builder and ceramicist specialising in rammed earth, who has worked with many architects. With Herzog & de Meuron he built the Ricola Kräuterzentrum at Laufen, Switzerland (2014), a large production building with rammed-earth walls prefabricated in blocks, laid like masonry and protected from rain erosion by thin layers of lime-trass mortar, more resistant than earth, inserted at regular intervals to slow down erosion. In Germany the Alnatura campus in Darmstadt (2019) has rammed-earth façades that help regulate the temperature and humidity of the offices. These buildings are very different from the schools of Gando and Rudrapur, but they spring from the same principle: studying how earth actually behaves, instead of regarding it as a material of the past.
For designers, even far from Africa or Bangladesh, the work of Kéré and Heringer offers some concrete guidance. First study the climate and the local way of life, and only then choose materials. Separate functions: a light roof that gives shade and shelter from the rain, beneath which massive walls store coolness. Use local materials where they offer real performance, without ideology, and combine them with industrial materials where needed, like the metal sheeting of the Gando roofs. Finally, treat the building site as part of the design: those who build a building become its first maintainers, and their skill is the best guarantee that it will last.