In Montpellier, a building made of rice bales and raw earth will rise from the ground on the Zac Hippocrate

L’entreprise Calyclay est chargée de la réalisation du bâtiment Midi Libre – GIACOMO ITALIANO

From 2025, the Zac Hippocrate in Montpellier will host Weko, an office and housing building of more than 4,000 m². Its particularity ? It is made of bundles of rice and raw earth.

The vacant lot, located on avenue Nina Simone in the ZAC Hippocrate in Montpellier, is currently deserted. At the start of 2025, it will house a building of more than 4,000 m of offices and 550 housing units. This Thursday, June 20, those involved in the construction site met to lay the first boot. Because the building will be made of rice bales produced in the Camargue and raw earth from the excavation of the site.

An ecological process

The method is simple: a concrete post-beam structure is filled with boxes of rice straw, coated with an interior coating of raw earth and an exterior coating of lime.< /p>

Laying the first truss of the Weko building. Free Midi – GIACOMO ITALIANO

Ariel works for the Calyclay company, which is responsible for building the project. The young woman, dressed in work pants speckled with ochre-colored earth, applies layers of coating to a prototype board. “This method has several advantages. The use of bio-sourced materials, mostly of local origin, reduces its carbon footprint”, she explains, between two strokes of the trowel.

“In addition to this virtuous short-circuit approach, these materials guarantee excellent thermal inertia for the building's walls. The building keeps the heat in winter and stays cool in summer”, points out her colleague Pauline.

The building, designed by architects François Leclercq and Olivier Navelet, will also be equipped with a ventilation system using an adiabatic air treatment unit, associated with air mixers.

A method that is still not widely used

"This is the future of building", considers Thierry Lacazio, deputy regional director of Vinci Immobilier, project manager. Constructing a building with earthen coatings, however, takes much longer than a concrete structure. “It’is almost twice as long", concedes Pauline.

Longer, but also more expensive. "Craftsmanship requires a larger workforce with rare training", she continues. Cost of installation excluding tax: almost 7 million euros. "This is a long-term investment. These installations are extremely durable. The first straw house was the Feuillette house in Montargis in the Loiret. In 100 years, it hasn't moved an inch".

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