By Alejandro Alva Balderrama

Earthen architecture is one of the oldest forms of construction. It is composed of structures made from unfired earthen materials, including adobe (or sun-dried mud brick), rammed earth, and a host of other earthen components and construction techniques that vary from culture to culture and region to region. Not only do earthen materials serve as the primary structural element in such architecture, they are also often used for rendering or for decorated surfaces.

Egypt Two views of tombs in the ancient Muslim cemetery in Aswan. The several hundred tombs at the site were built between the 8th and 12th centuries. Photos: Eric Blanc.

The tradition of building with earth is evidenced the world over. In many parts of Africa, Asia, and Central and South America, earth remains a prevalent building material. According to the United Nations, an estimated 30 percent of the world's population lives in houses made of earth.

The variety of earthen structures ranges from simple forms to vast, monumental sites of high complexity. Indeed, earthen sites compose 10 percent of the World Heritage List of UNESCO. But many significant sites are threatened; 16 of the 100 places on the World Monuments Watch 2000 List of 100 Most Endangered Sites—as well as 57 percent of the sites of the World Heritage List in Danger—are of earthen construction.

Commonly perceived as only a vernacular form of architecture, new earthen construction—abetted by the environmental movement—has seen increasing standardization and industrialization in recent decades. But the conservation of earthen architecture has been slower in its evolution. Progress in conservation and in new earthen construction is in many ways interreliant; the continuity of the tradition of building with earth informs conservation practice, while preservation of this important architectural legacy inspires its future use. Yet conservation of earthen architecture is still coming into its own as a discipline.

Two series of events in the last 30 years have profoundly affected the development of the field. The first is a sequence of international conferences on earthen architecture conservation that began in Iran in 1972. Eight international conferences have been hosted in total, the most recent in Torquay, England, in May 2000. Each conference made its mark on the earthen architecture landscape by articulating the needs of the field, motivating particular activities, and promoting a network of practitioners around the world.

The second set of events was a series of educational activities for professionals in the conservation of earthen architecture. The Pan-American Courses on the Conservation and Management of Earthen Architectural and Archaeological Heritage (known as the "PAT" courses) offered from 1989 to 1999—in addition to a host of regional workshops, courses, seminars, and other educational initiatives—built skills in this challenging area of conservation and advanced the field of study related to earthen architecture conservation. As with the conferences, these activities have fostered the development of the field. The exchange between the more global conferences and the specific educational activities has itself spawned important field projects, research initiatives, and advocacy efforts.

An Awakening Interest

Morocco Top and middle: Two Casbahs in the Dades Valley, sometimes called the valley of a thousand Casbahs. Bottom: A Casbah in Tifoultoutte, overlooking the Drâa Valley. Photos: Eric Blanc.

In some places, earthen architecture dates back millennia, while in others it represents a recent development. Today it is a growing field. New avenues are opening for its study as this building tradition comes to be recognized as an indispensable part of our heritage. There is new interest in conserving culture through the development of earth-building skills. The tradition embodied by the various cultures of construction—using earth or other materials—is not, as cultural homogenization would suggest, "an illusion of permanence." Rather, such a tradition provides a foundation for a modernity that acknowledges specific identities. Today more than ever, such approaches are needed to respond to cultural homogenization and globalization, which threaten the values, origins, and expressions of identities of countless communities.

Interest in the study and conservation of earthen architecture grew during the last half century. The 1950s and 1960s witnessed the first formal indications of this interest. At the first inter-national conference on earthen architecture, held in Iran in 1972, the keynote address acknowledged earthen architecture as "the oldest and most widespread" architectural expression of our monumental heritage.

The recommendations that grew out of subsequent meetings reflected the vast array of issues in the field. In part, the conferences contributed to an awakening of a consciousness regarding monumental earthen architecture and its pervasiveness. But just as importantly, the gatherings also noted the necessity to promote the conservation of earthen architecture through study and the application of conservation skills.

For many years, these conference conclusions remained mere declarations. Efforts to take on specific problems—particularly in archaeological zones—consisted mostly of "solutions" to problems encompassing only small areas of physical material. This approach grew out of the widely held orientation of traditional conservation toward solving material problems by modifying the physical and chemical properties of the original material—or, in the best of cases, through some protection of exposed structures.

The plenary sessions of these international conferences not only recognized the importance of our architectural heritage built of earth but also encouraged a comprehensive exploration of issues involved in conserving that heritage. In relating the conservation problems of earthen architecture to issues of education, research, professional practice, public awareness, methods, and other elements of this complex cultural expression, it became clear that earthen architecture conservation could not be reduced to an intervention aimed at stabilizing or consolidating a given surface or wall. Treatment with such and such a product or a focus on a stabilized square meter or square centimeter were not approaches that successfully could promote the conservation of such an enormous, yet fragile, architectural heritage.

The Need for Education

While the fourth international symposium on earthen architecture, held in Peru in 1983, reiterated the need for intensive educational programs, it was not until the fifth symposium in Rome in 1987 that the International Centre for Earth Construction-School of Architecture of Grenoble (CRATerre-EAG) assumed responsibility for such programs. Two years later, the International Centre for the Study of the Preservation and Restoration of Cultural Property (ICCROM) agreed to share that responsibility.

	Turkmenistan Two of the remaining structures at the ancient site of Merv, which dates back to the 6th century B.C.E. A series of cities occupied the site for a period of over 2,000 years. Photos: Neville Agnew.

Educational activities in the period from 1989 to 1994 brought the complex character and needs of earthen architectural heritage to the attention of the academic and professional communities dealing with architecture and its conservation. To preserve the cultural tradition of earthen construction, a dialogue was required between conservation-oriented disciplines and disciplines focused on new construction and planning. It was necessary to emphasize the relationship between tradition and modernity as a way to preserve earthen architecture as a resource and a "constructive culture." In terms of training, this meant teaching those charged with the conservation of earthen architecture about construction materials and techniques. They needed to experience the use and application of earthen materials in order to understand their behavior and preservation. At the same time, those engaged in new construction needed more understanding of the past. Only a vision for the future based on a profound knowledge of history and of local and regional traditions could counteract the devastating effects of acculturation.

China Clockwise from left: Earthen remains at Jiaohé, a Silk Road site in northwest China. Photo: Francesca Piqué. Two rammed-earth, multistory defensive dwellings constructed by the Hakka people in Fujian Province. Photo: Neville Agnew. The Jade Gate, the west end of the Han dynasty's Great Wall. Photo: Po-Ming Lin.

The 1989 agreement between CRATerre-EAG and ICCROM on educational programs led to their formation of the Gaia Project, which conceived of creating intensive on-site education. Initial optimism for the institution of an on-site educational program rapidly faded in the face of a series of obstacles. Then, in 1994, a proposal from authorities in Peru and contact with the GCI Training Program resulted in the institutional cooperation that led to the joint organizing of PAT96, the first major on-site educational program on the conservation of earthen architecture. Later, another agreement was reached for developing a new institutional collaboration program between CRATerre-EAG, the GCI, and ICCROM that would supplant the Gaia Project. Called Project Terra, the initiative organized PAT99. Today it serves as an institutional framework for the Terra Consortium and for several research activities now under way.

Regional Efforts

Mali Top: The mud brick mosque in the city of Mopti on the Niger River. Bottom: Granaries in the village of Banani, east of Mopti. Photos: Guillermo Aldana.

While policies and approaches can be promoted internationally, substantive action must occur at the local and regional levels. During the 1990s, several regional activities significantly advanced the cause of earthen architecture. Of particular importance was work in Portugal, England, and Italy.

In Portugal, the Bureau of Buildings and National Monuments (DGEMN) assumed responsibility for organizing the seventh international conference of earthen architecture—Terra93, as the event was known. Besides working for broad international professional participation at the conference, the DGEMN promoted earthen architecture conservation education among professionals and the general public with the opening of the "Des architectures de terre" international exhibition in Lisbon. At the conference, the basis was laid for what would later be PAT96 and then PAT99. In addition, among other efforts, the DGEMN encouraged the earthen construction of the new municipal library in the historic city of Silves (the venue for Terra93) and the establishment of a course for craftsmen of earthen construction at the Escola Nacional de Artes e Oficios Tradicionais in the Portuguese city of Serpa.

The Terra93 conference also helped spark other regional initiatives, including the 1994 "Out of Earth" conference in Devon—the first national conference in the United Kingdom on the conservation of earthen architecture. This conference followed the creation of the Earth Structures Committee of ICOMOS/UK and the establishment of the National Centre for Earthen Architecture at Plymouth University in Devon—both of which were encouraged by English Heritage. All three organizations together hosted the 8th International Conference on the Study and Conservation of Earthern Architecture, held in Torquay, Devon, in May 2000.

France Top: A typical farmhouse in Brittany, probably over a century old. Bottom: A family house in the Alsace region.Photos: © CRATerre-EAG.

An important aspect of Terra93 in Silves was the Italian presence, with representatives from Sardinia and others from academic and professional communities. Italian interest in the study of earthen architecture extends back several decades; today, there are no less than nine study groups centered at Italian universities working on research and education for earthen architecture. In addition to these groups, there are a number of professional associations for the study and promotion of earthen architecture in various regions of Italy. Certain regions such as Sardinia and Abruzzi have strong cultural support—and therefore political support—for the traditional use of earthen architecture.

The Italian experience is characterized by academic and scientific rigor, the integration of methodologies for planning the conservation of historical centers built out of earth, and the opportunity for defining a national policy for the study and conservation of earthen architecture, based on a major cultural movement that promotes it. A milestone event was the Conference of Quartu Sant'Elena in 1990, the first of a series of events in Italy that led to the establishment of the National Association of Districts of Earthen Architecture. This association of municipalities with a tradition of earthen architecture is significant because of the strong influence that Italian regional governmental authorities have on the management and development of the built and natural environment. The charter of the association was signed at another conference in Quartu Sant'Elena—Terra Cruda 2000—held 10 years after the first.

Action for the Future

United States From top to bottom: Two homes in Geneva in upstate New York, constructed of mud brick in the 1840s. Photos: Richard Pieper. The Taos Pueblo and the Sacred Heart Church at Nambe Pueblo, both in northern new Mexico. Photos: Eric Blanc.

The vision and hard work of innumerable persons contributed to the initiatives and events mentioned above. Of equal importance was the role played by international organizations. These organizations have facilitated, promoted, and—with their presence and authority—sanctioned these valuable efforts. They likewise have contributed to the dissemination of ideas, placing them in a world perspective and facilitating access to information.

Still, it would be an illusion to treat such achievements as indicative of overall success in the study and conservation of earthen architecture. While in some regions it is now more possible to improve policies regarding this heritage, the majority of the world has yet to implement significant measures promoting earthen architecture and its conservation. Entire regions where earthen architecture is a fundamental part of the culture and heritage have been insufficiently influenced when it comes to responding to architectural acculturation. The historical heritage of earthen architecture is in jeopardy, disappearing from a great part of the planet either through negligence or because it is being replaced by other forms of construction. Governmental authorities frequently consider earthen construction to be substandard, even though it may meet the housing needs of the population more appropriately than other building materials and techniques.

In a handful of cases—after years of academic, institutional, and professional efforts—some earthen architectural heritage enjoys a degree of sponsorship, thanks to legislative action. Achievements have also been made in creating awareness as to earthen architecture's importance. In addition, the lists compiled by international heritage organizations have had some effect in retarding irreparable losses of these treasures. In rare instances—at Chan Chan in Peru, at Joya de Cerén in El Salvador, and in a few historic city centers—comprehensive measures are being put in place for long-term preservation. Even so, the concepts of planning and management still lack sufficient acceptance in the field of conservation to be able to redirect efforts away from traditional, narrowly focused treatment approaches.

In coming years, as the architectural acculturation already under way becomes more acute, new, ongoing, and diverse responses for conserving earthen architecture will be needed. Such responses must integrate all the issues involved and take into consideration the vast range of local and regional conditions.

Contemporary Production of Earthen Material Top to bottom: The production of mud bricks for homes, just outside Addis Ababa, Ethiopia. Photo: © CRATerre-EAG. Mud brick production for use in the construction of homes in Yunnan Province, China. Photo: Neville Agnew. Mechanized production line of stabilized compressed earth blocks in Isère, France. Photo: H. Guillaud (© CRATerre-EAG).

In some instances, these responses will find support in legislation that imposes regulations to protect the heritage. In other cases, support will come through the promotion of planning and management, or through capitalizing on ecological agendas, such as bioarchitecture and sustainable construction. The ecological approach suggests scenarios in which the conservation field—in its own interest—will have to promote new earthen construction and planning. International organizations will need to encourage specific activities in specific regions to increase political and administrative awareness of earthen architecture. Because all political and administrative responses are founded upon a solid cultural base, these movements must be built upon that base. The issue of conserving earthen architecture is no exception.

The conservation of earthen architecture requires an integration of actions: cooperation, the synergy of disciplines and initiatives, building and maintaining institutional and professional networks, the promotion of study, and a rigorous consideration of cultural diversity. Even so, we should not be obligated—for the umpteenth time—to justify our concern over the issue, in particular among the professional community and institutions presumably interested in conserving this heritage. Paraphrasing the text of an amusing book published several years ago, we could say, "There are so many without whom all of the above would have been impossible. There are many others [who fortunately are less in number] without whom all this would have been a heck of a lot easier."

A renewed commitment to the conservation of earthen architecture and the promotion of its values is essential for this heritage to be universally recognized as an area of study and of professional practice. And it is the study of earthen architecture—and a continued search for new and better ways to conserve it—that will allow us to build upon the foundation of a field already rich in reflection, conviction, and passion.

Contemporary Buildings Constructed from Earthen Material Clockwise from top left: Housing in Auroville, India, and Isère, France. Photos: S. Maïni, T. Joffroy (© CRATerre-EAG). An exhibition building in Janadryah, Saudi Arabia. Photo: T. Joffroy (© CRATerre-EAG). A modern structure in Cairo, Egypt. Photo: Eric Blanc.

Alejandro Alva Balderrama is the director of the Program on Architecture and Archaeological Sites of ICCROM and codirector of Project Terra, a collaborative project of CRATerre-EAG, the GCI, and ICCROM.