Promoting raw earth instead of concrete to change the paradigm

For his master's project in architecture, Jeremy Morris analyzed the cycle of construction materials in the canton of Vaud. His study shows that more regular use of raw earth could reduce the sector's carbon impact. The architect proposes three measures to achieve it.

The construction sector contributes 39% of global greenhouse gas emission rates, 11% of which result directly from the manufacture of building materials such as steel, cement and glass. The systematic use of concrete is currently one of the main obstacles to reducing this heavy carbon footprint. Changing this practice has thus become the priority of many architects and engineers aware of this issue. This is the case of Jeremy Morris, who, as part of his master's work in architecture at EPFL, became interested in the concrete cycle in the canton of Vaud. His study identified three measures that open up avenues for reducing its use by favoring that of raw earth.

Currently, earth excavated during construction is one of the biggest wastes in the world. In Switzerland, and for each canton, the equivalent of a Cheops pyramid, or 2 million cubic meters, comes out of the ground each year. This excavation material, considered by law as waste, is treated and spread on agricultural land, raising crops by several meters, sometimes reaching saturation. How can this sustainable and recyclable material be better used in construction? This is what the young architect, also a videographer, wanted to understand.

Change the law

To achieve this, the student drew a map of the Canton of Vaud identifying all the stages of the construction sector, from the Sarraz extraction areas, which are used to produce cement, to the 67 landfill areas. “In the Canton of Vaud, the companies that manufacture concrete are the same as those that dig the earth for new construction sites. They therefore have no interest in reinjecting this material into the construction,” explains Jeremy Morris, who went there to shoot many images.

The architect therefore proposes as a first measure to change the legal status of the excavated material, in order to change it from “waste” to “resource”. "Raw earth can be built and deconstructed, which is more difficult for concrete, the use of which should really be limited to structural elements of buildings and civil engineering infrastructures", comments the graduate.

Financial support

The use of raw earth is however expensive compared to concrete, which remains the cheapest solution, despite its heavy environmental impact. The architect therefore proposes as a second measure state support for this type of construction, until a true circular economy is put in place. "France has recently built nearly 400 homes in raw earth from excavations made in Paris thanks to European support", illustrates the architect, who also cites Belgian examples. The know-how in this type of construction is quite developed in Switzerland, but its implementation in construction could be more advanced, according to the architect.

Training and research

Its latest measure therefore promulgates continuing education in rammed earth and raw earth, two techniques that resort to the use of sustainable and renewable materials, to limit the systematic use of concrete by practitioners in place. It also logically calls for full and complete integration of this training into the Swiss academic curricula of the construction trades as well as financial support for research into this technique, in order to further improve its potential.

"I'm not naive, I know that these measures require a lot of effort," says the architect. "But a radical change in the vision and philosophy of architectural and construction practice must be made, by putting in place more cooperative processes between systems, in order to achieve a more circular economy". Jeremy Morris built mud bricks himself during his master's project, to understand the logistics of producing the material and to feel it with his own hands. “This step convinced me even more of the beauty of this technique and its relevance.”

> Further information: EPFL - Master Thesis