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"Mud, besides being mercifully cheap, is undeniably beautiful: Structure dictates form and the material imposes the scale. Within the limits imposed by the resistance of mud and by the laws of statics, the architect finds a sudden freedom to shape space within the building, to enclose a volume of chaotic air, and to bring it down to order and meaning to the scale of the human being."
Hassan Fathy (1900-1989)
SUSTAINABLE CONSTRUCTION WITH EARTH
Earth as a building material is used since ancient times and has a long history of different applications and techniques.
All over the world historical buildings and emblematic structures remain as evidenced by more than 100 sites inscribed on the World Heritage List of UNESCO, with examples like part of the Great Wall of China, the complex Alhambra in Granada, or the mosques and homes in Timbuktu, Mali.
Rammed earth part of the Great Wall of China, started to build in the V century B.C.
Several studies show that nearly 3 billion people in the five continents lives or works in buildings constructed with earth, so the relevance of this topic in a social and economic perspective reveals itself to be universal.
Presented in both traditional and modern architecture styles, in developed countries as well as in countries with economical needs, earth reconciles in practice the cultural component with the social dynamics, ecology and economy, laying the groundwork for a real constructive and sustainable development.
Earth clay breathable renderings ©Lehm
In Portugal, the use of earth has its origin in Prehistory as demonstrated in several archaeological sites, and later strongly influenced by the Arab presence in the Iberian Peninsula. The geological and climatic factors, especially in the southern region of the country, related with the historical and cultural roots were always favorable to its use. All over the country it can still be found numerous earth buildings, built with traditional techniques like of Rammed Earth, Adobe and Wattle & Daub.
After a period of gradual abandonment in the 60s, today we witness the returning of these techniques, based on an ecological and sustainable concept of the material, and the introduction of new technologies that open up a positive outlook for the future of earth construction.
Building a rammed earth house, Ferreira do Alentejo, Portugal, 1955 ©OAPIX
Earth_ Understanding the material
Earth construction is the use of subsoil material in result of 2 natural actions: erosion and sedimentation. It is generally taken from the terrain and prepared and used in the construction without processing.
When compared with others earth is an available, reusable and not industrially processed material. Its use allows a real saving of means, expended energy and costs reflected in the processing, transport and its application.
This economy remains during the building timeline until its demolition and even in its recycling process. When an earth building is demolished all its major components can go back to where they came from. The entire cycle can be restarted then.
Earth also presents a good thermal performance by its high thermal inertia which enables the indoor spaces to be cool in summer and warm in the winter, not allowing the entrance of cold and heat. Thus, earth can help to reduce the temperature ranges and energy consumption throughout the building lifetime, along with its behavior towards the fire and its excellent acoustic performance.
Building a rammed earth house, Odemira, Portugal, 2007 ©Pedro Abreu
PERSPECTIVES TOWARDS THE FUTURE
Earth construction presents itself as an ecological solution with many technical advantages, allowing a sustainable management and effective conservation of natural resources.
On other hand, when we look at the past, we can easily find on historical earth buildings an extraordinary and intangible synthesis that crosses time.
The future of earth construction must come alongside with innovation, scientific research, material development and technical training.
Building with earth in the future represents a commitment between tradition and technology, actively contributing to the debate on key issues of modernity such as sustainable development, social and economic inequalities and cultural diversity.