Ydéal: Spotlight on Rammed Earth Construction

In a context of urgent climate and environmental imperatives, rammed earth construction is an increasingly attractive option.
An example in Block B2, with the L’Orangerie in the Ydeal project

 

 

In La Confluence, in Block B2, a three-story office building, L’Orangerie, is being constructed with the rammed earth technique under the management of Clément Vergély Architectes and the contracting authority of OGIC. The walls of the building’s first floor are produced on-site first, so they can dry before being assembled. The walls of the second and third floors will be made as the project progresses, beginning in April 2019. This is a first for a project of this type, notably featuring 5 arches.

Nicolas Meunier is a designer/builder of rammed earth buildings in Chambles, in France’s Loire region. He’s in charge of this part of the project, and he presented this material’s characteristics to us.

 

Durability

In the Lyon urban area, rammed earth construction now accounts for 20,000 housing units. Far from being limited to use in heritage-centric projects, it’s an integral part of an economic and environmental approach (short supply chains - the earth used is from construction sites in Saint-Quentin-Fallavier, 30 kilometers from La Confluence, 100% recyclable, etc.). There is one constraint, though: timing. Rammed earth is usually produced between April 1st and October 30th, to prevent the risk of freezing temperatures disintegrating the still-fresh material. The blocks of rammed earth are made either with a machine that creates sized walls, or using formwork.

 

Comfort of use

One advantage of rammed earth construction is its excellent hygrothermal properties (indoor temperature and air humidity), thanks to the use of clay. This is because clay absorbs moisture in the air. Even when it’s dry, rammed earth contains at least 1% water (7% to 8 % when it’s wet). In cold weather, condensation causes the material to reheat, which, in turn, keeps the indoor temperature steady for longer. Compared with conventional construction techniques, rammed earth can generate savings equivalent to up to 2 months of heating per year. In summer, it’s the opposite: the moisture evaporates and keeps the building cool. This form of natural heating and cooling only works when appropriate coatings are used, so the rammed earth can “breathe”.

 

Resistance and control

The dry material is eight times more resistant than when it is wet. It reacts very well to compression (one square meter can bear up to 30 or 40 tons). Rammed earth can thus be used easily for buildings of up to three stories, or even slightly more, depending on the configuration. For this project, Nicolas Meunier is being assisted by the ENTP (National Public Works Institute) in Vaulx-en-Velin, which is conducting various studies on the material. Factoring the constraints of this material into the future building’s design means that, in particular, the project’s costs can be controlled.

 

2000
logements en pisé dans la région lyonnaise

 

30

nb de kms parcourus par la terre

 

Zoom

Un inventaire participatif


 

A l’occasion de l’exposition « Ma terre première pour construire demain » (23 février- 17 juillet 2016) a été lancé un inventaire participatif. Coordonné par l’architecte Emmanuel Mille et mis en œuvre par le Musée des Confluences, il avait pour objectif de répertorier toutes les constructions en terre crue.

En savoir + :
http://patrimoine-terre-lyonnais.patrimoineaurhalpin.org

 

 

In a context of urgent climate and environmental imperatives, rammed earth construction is an increasingly attractive option.