With its roots in all ancient civilisations across the world, earth construction is gaining ground as a sustainable, economic alternative to concrete
Traditional and contemporary art of raw earth construction are both absent from even the most recent books on architecture, disregarding its due importance, and its true diversity, quality and modernity. With some notable exceptions, this ignorance has produced a lack of reliable information about the future uses of this natural resource as a locally sourced and ecologically sustainable building material. The dearth of information is the result of a sustained and profound crisis of cultural amnesia. Remedying this missing knowledge would allow a wide range of architectures to be built in situ, in both emerging and industrialised countries.
‘While an essential civic and ethical duty to fight against the climate crisis is belatedly being adopted in new architecture, raw earth offers architects the potential for action’
Used continuously for millennia in most of the world, raw earth remains one of the most popular construction materials. In 1964, anthropologist Claude Lévi-Strauss drew attention to a duality at the heart of civilisations: the use of ‘raw’ and ‘baked’. These are not confined to applications in food but relate to architecture too: earth allows both treatments. The oldest, still widely adopted in many countries, uses solar heat to dry and harden earth, unlike baked bricks or tiles which require much higher temperatures. Raw earth has many virtues and advantages, in particular in terms of energy saving and ecology. Most varieties of soils can be adopted if they include appropriate granular substances: pebbles, shingle, sand, silt and clay. This earth must always be extracted under the layer having an agronomic vocation. There are a dozen construction techniques, including compressed, moulded, extruded and poured earth. The three most common for load-bearing masonry are adobe (modular sun-dried bricks), rammed earth (compressed in lateral forms to build monolithic walls, often 500mm thick) and its variant in cob (used without formwork). A hybrid design combines a load-bearing structure (most often timber) filled with wattle and daub. In addition to walls, adobe can also be employed to construct a wide range of arches, vaults and domes.
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Remarkable and ingenious earth architecture can be found on all continents, and surprisingly often in Europe. Over time, techniques have been rationalised and rammed earth can now be prefabricated in situ in large masonry modules. As a substitute for adobe, the more resistant compressed earth blocks (CEB) can be stabilised with cement – although scientific studies by French interdisciplinary group CRAterre have demonstrated this is unnecessary as long as the design is kept simple, efficient and so fully ecological.
While an essential civic and ethical duty to fight against the climate crisis is belatedly being adopted in new architecture, raw earth offers architects the potential for action, especially for buildings of small or medium size, which are the most prevalent. Raw earth does not require a phase of industrial processing and needs little or no transportation, as it is used on or near its place of extraction. Its use does not require fossil fuels and does not produce CO2. If used, as often advised, without cement or any other industrial additive, earth is a fully recyclable material. Universally, whatever the country, inhabitants of these bioclimatic habitats confirm that it is cool when the external temperature is hot and vice versa. This natural and living material, with warm colours and sensual textures, provides both precious thermal comfort and is a daily pleasure to live with, unlike standard industrialised and soulless materials.
‘The famous Tower of Babel was built of earth in 1970 BCE, rising to 70 metres in height: the first ‘skyscraper’ in history’
Building with raw earth adheres as much to productivist logic as it does to self-help construction, allowing modest families and communities to realise one of their most essential hopes and needs: pleasant, healthy, economical and sustainable housing. It is a major contribution to social wellbeing, especially as it proves compatible – today and historically – with the expectations of all social classes, from the most affluent to the most deprived. In addition, this material encapsulates many hopes and watchwords for ecological architecture: ‘improving building through less industrial input’, ‘reconciliation between global and local’, or ‘sobriety as a harmonious and rewarding way of creativity’. Last but not least, raw earth is often a credible alternative to cement (and concrete), the production of which involves between 6 and 8 per cent of the world’s annual CO2 production – a disastrous balance and a major scourge that threatens the very foundations of our civilisation.
It all started around 10,000 years ago, during the ‘Neolithic Revolution’, which heralded the transition from nomadism to the first human settlements. The agricultural surplus economy of the early villages led to the creation of the first cities. If Anatolia hosted, from 7560 BCE, the most ancient proto-city – Çatal Hüyük – it was in Mesopotamia, on the Fertile Crescent (Iraq and Syria), that the first great urban civilisation appeared and grew.
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Source: Al-Rawda Archaeological Survey
To build its numerous agglomerations – sometimes already enlarged to the status of metropolises like Babylon – and given the scarcity of stone and wood in those regions, raw earth was the predominant material. It was used to build not only most homes, but also fortified defensive walls, palaces and temples, and in particular ziggurats, whose ascending architectural impulses had to ensure a mystical connection between men and gods, between earth and sky. The famous Tower of Babel was built of earth in 1970 BCE, rising to 70 metres in height: the first ‘skyscraper’ in history.
Ancient Egyptian civilisation is often perceived as having favoured stone, as the pyramids and the central parts of the temples dedicated to the late pharaohs testify. This material had indeed to ensure the eternal survival of places devoted to the worship of the dead. Although the temples’ central cores dedicated to the deceased elites were made of stone, the vast surrounding priests’ accommodation, huge food regional reserves and high defensive walls were built of earth as were almost all inhabited villages and cities. This material proved to be so strong and durable that even military fortresses were erected the same way, such as the gigantic structure of Buhen, built in the 19th century BCE.
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From its birth in the Middle East during the seventh century, Islamic civilisation borrows, through cultural osmosis, some architectural characteristics which had been initiated in Mesopotamia, including the art of building with earth. Today, the living historic cities of these regions – like the magnificent Yazd in Iran – bear witness to this powerful heritage. The Arab Conquest, extending from Central Asia to Southern Europe, via North Africa, ensured the geo-cultural transfer of this know-how, assimilating other influences along the way, such as that borrowed from the Berbers of Morocco who had already mastered rammed earth. With this technique, the Arab-Muslim culture built its most sumptuous palace in Spain: the Alhambra of Granada erected in the 13th century. In their turn, since 1492, the Spaniards exported this technical know-how to Latin America to build more than a hundred cities of colonisation and innumerable churches and even cathedrals. Yet well before the arrival of these conquistadors, local cultures had already excelled in earth construction and built masterpieces, such as the ‘pyramid’ of Huaca del Sol in Peru from the first century, or the huge city of Chan Chan inhabited from the ninth to the 15th century. In what is now the US, the very early creations (3300 BCE) of the Mound Builders were developed along the Mississippi Valley, and in New Mexico the oldest Indian pueblo community of Taos dates from the 13th century. As for China, its engineering genius was deployed for almost a millennium to build multiple Great Walls whose constructive intelligence consisted in using only local materials: stone but also raw earth on very long sections. The tulous, circular villages of the Hakka people built of rammed earth from the 12th to the 20th centuries, are still also a marvel of cultural and social ingenuity.
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In Yemen, the villages of the Hadramut Valley and especially the ancestral city of Shibam constitute amazing masterpieces of harmony and adaptive intelligence to a hostile environment and climate. This compact city (about 7,000 inhabitants living in approximately 8 hectares) is the only one in the world to be entirely built in adobe with all of its residential buildings rising to five to seven storeys.
In Morocco, the pre-Saharan oasis valleys are rich with hundreds of (often fortified) stunning villages (ksour, or singular ksar) built of rammed earth, testifying to the constructive genius of the Berbers. The best preserved ones are those of Aït Ben Haddou and Tissergate; as well as the kasbahs – fortified residences of tribal chiefs – of Taourirt in Ouarzazate and of Amridil in Skoura. The urban treasure of the country remains in the old medinas (Marrakech, Fez, Rabat, etc), the only ones in the Arab-Muslim World to have fully kept their original powerful architectural and urban specificities, such as their defensive enclosures which total more than 100 kilometres of high rammed-earth walls. In Mali, the ancestral city of Djenné reveals a remarkable symbiosis between local animist cultures and those originating from Morocco and Islam. This later influence has generated magnificent traditional and modern mosques of architectural and ‘sculptural’ power unparalleled outside West Africa, the most celebrated being in Djenné, built in 1907. In Mali, this vivid vernacular creativity remains alive and still creates masterpieces.
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This art of building with earth is not confined to these regions – it can also be appreciated all across Europe. Great Britain has a large regional heritage of cob cottages (mainly in Devon), yet to be re-evaluated. In rural and urban France, abundant historical, vernacular and contemporary buildings coexist in rammed earth (pisé), adobe, cob (bauge) and wattle & daub (torchis). The surprising worldwide diversity of this heritage has inspired a new or even radical creativity, often evoked as belonging to Critical Regionalism as propounded by Kenneth Frampton.
Three great pioneers generated long-lasting global modernisations in earth construction. The first one involved with its theoretical and practical rationalisation and generalisation was the French master-mason François Cointeraux (1740-1830). From 1789, in the spirit of the ideals of the French Revolution, he invented his nouveau pisé, an innovative version of traditional rammed-earth. It was intended to promote housing widely accessible to all social classes and to develop economical, comfortable and non-combustible architecture. His many militant writings were translated into nine languages, ensuring an enduring dissemination of his ingenious inventions.
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The Egyptian architect Hassan Fathy (1900-1989) was, from the 1940s, the first to prefigure another revolution – that decreed by the Bandung Conference (1955) which brought together 29 emerging countries to refuse an alignment between both capitalist and communist ideologies, to promote a third way: then coined the ‘Third World’. Its radical strategy advocated political, economic, cultural and technological self-sufficiency; it even developed an attempt to boycott imports of cement. Fathy’s early answer was to regenerate the adobe ancestral Nubian tradition to promote community based self-help construction. From the 1970s, his passionate creativity – experimented in the village of New Gourna – inspired many young architects, first in the US and Europe, and later only in the so-called ‘Third World’.
In France, CRAterre was founded in 1979 and based in Grenoble at the school of architecture. Since then, it has become the most pioneering, creative and important international interdisciplinary group in the field of earth construction. Its 60 researchers, practitioners and teachers are active and influential in many countries. They are responsible, in particular, for the design and management of exemplary projects, the development of an essential new theoretical and practical pedagogy focused on the mastery of raw earth design, as well as the worldwide inventory of all traditional and modern techniques: their Earth Construction: A Comprehensive Guide (ITDG, London, 2008) has become – along with other publications by them – an essential reference work for builders.
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In addition to the strategies and best practices promoted over two centuries by these three giants of innovation, countless architects and engineers have deployed their talents to follow their teachings or explore other creative paths. Many protagonists have, however, been unfairly overlooked. In the UK, architect Henry Holland (1745-1806) was the first enthusiastic translator of Cointeraux’s writings, which were influential in the US and Australia. From 1910, G Somers Clarke & WJ Palmer-Jones, disciples of the Arts and Crafts movement, built luxury villas in Egypt. Following the two World Wars, Clough Williams-Ellis suggested, in vain, that some of the destroyed habitats should be rebuilt with earth. From 1919 and 1945, Germany was in fact the only country to adopt an ambitious national strategy which would total more than 80,000 houses erected in earth. Rudolph Schindler from 1912 and Frank Lloyd Wright in 1940 were among the famous architects in the US to contribute to research into earth building – albeit never physically realised – as was Le Corbusier in France between 1940 and 1947.
In the US during the 1960s and ’70s, the Counter Culture revolution initiated the first alternative eco-houses, which were influential especially in New Mexico, where the combined use of raw earth and solar energy gave birth to ‘Solar-Adobe’ houses designed by Steve Baer and David Wright. Antoine Predock built the seductive residential estate of La Luz (60 upper-middle-class adobe houses in Albuquerque, completed in 1974): a model of compact urbanism designed as a realistic substitute to absurd American suburbia.
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During the 1980s CRAterre brought its technical skills to the new and influential momentum ensured by the construction of two major pioneering projects for social housing – the urban estate (64 units) of the Domaine de la Terre in France, and a pilot programme of 30,000 rural dwellings in Africa on the island of Mayotte. The activism of CRAterre has also stimulated young talents worldwide, including Anna Heringer in Germany and Martin Rauch in Austria. Their achievements – always without the use of additional ‘stabilisers’ such as cement – bear witness to the decisive contributions of a new generation of builders. Their architecture is not only perfectionist, rationalist and harmonious, but also ethical and ecological.
Since 1990, the use of rammed earth (unfortunately often overdosed with cement) has multiplied in the construction of luxury villas in the US, a creativity in which Rick Joy excels. In Australia, this practice had been initiated as early as 1952 by GF Middleton and has since become widespread. In addition to housing for the middle classes, it includes the construction of sophisticated rammed-earth buildings with a variety of programmatic uses. In Africa three talented ‘earth architects’ have emerged. From 1980, Elie Mouyal in Morocco with his seductive villas for the elite; from 2000 Francis Kéré in Burkina Faso with his ingenious and innovative rural schools and medical centres; and from 2010 in Niger, Mariam Kamara with her radical mosques and housing programmes. All three auguran African cultural future finally freed from post-colonial alienation.
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Various Pritzker Prize winners have created rammed-earth masterpieces, including Wang Shu in China with his remarkable Wa Shan Guest House on the Hangzhou campus (2013), and Renzo Piano in Uganda with his children’s hospital (2019). Other giants of the art world – such as Andy Goldsworthy, Richard Long and Hannsjörg Voth – have given new impetus to Land Art in the form of their eco-works with raw earth.
Today creators are confronted with innumerable difficulties: restrictive regulations, absurd standards, a pettifogging bureaucracy encouraging standardised solutions, and a dominant techno-structure tending to curb alternative creativity in favour of the prescriptions of multinational industrial groups. Projects conceived in raw earth are too often hampered by these scourges. As Rudy Ricciotti states, ‘architecture is a combat sport’ which now allows only truly gifted and motivated actors to overcome these obstacles and contribute to the progress of a required alternative route. In addition to the political reforms to circumvent these obstacles, an absolute priority is the appropriate training of future professionals, from designers to craftsmen, who will be able to master all aspects of earth construction. However, in 2020 there is still only one school of architecture worldwide (Ensag in Grenoble) to grant ‘state diplomas’ related to this specific pedagogy: the one initiated by CRAterre. Their example, with proven effectiveness and realism, should now be adopted by a much wider range of schools of architecture and engineering. In instigating this ‘cultural and educational revolution’, architect Patrice Doat has paved the way to secure our future.
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Source: Joly & Loiret, L+R, Amateur Architecture Studio
A promising move in the right direction is the ambitious project for a large multi-purpose urban estate at the gates of Paris by Quartus, the developer who commissioned Wang Shu to design the urban plan, and entrusted the technical design and the architecture to a team linked to or trained at CRAterre. This pilot project will also demonstrate the feasibility of a promising new form of circular economy in urban areas: the earth used will be soil extracted from the Paris metropolis during the digging of the tunnels of the new metropolitan rail network. So it is a huge new field of potential activity that is taking shape in all agglomerations.
It will soon allow earthen architecture to flourish again in urban areas. In the words of the philosopher and sociologist Edgar Morin, ‘the great movements of transformation always start in a marginal, deviant, modest or even invisible way’.
Further reading: The Art of Earth Architecture: Past, Present and Future, Jean Dethier, Thames & Hudson, London, March 2020
Lead image: Near the town of Saada in Yemen builders use the zabour technique of rammed-earth construction. Courtesy of Pascal & Maria Maréchaux
This piece is featured in the AR February issue on Soil – click here to purchase your copy today