Maison Empreinte: review and feedback from a construction site unlike any other

To reinvent construction, the strength of collective innovation

Empreinte was launched by ERB, Entreprise Générale du Bâtiment located in Chalones (49), in September 2020. From the first months, the collective shook up the codes of the sector.

“To rethink the habitat, Empreinte has bet on the collective from the design stage: the partners have come together to question the traditional processes of the sector and improve the performance of the deployment of each person's expertise. A decisive step which remains today an unprecedented methodological innovation” notes Michel Ballarini - CEO of Alter, developer of the Echats III eco-district in Beaucouzé, in which the house was built.

The project was launched in the spring of 2021 and was open to professionals in the sector as well as to the general public, to allow the widest possible appropriation of the approach. More than 1000 visitors went there.

“Empreinte wanted to bring together actors who share the desire to rethink the impacts of construction and housing. This first project was a demonstrator, a full-scale test of methodologies, technologies and deployment of materials. He showed us that changing the way we build was possible, and that together these changes make us perform better” explains Thomas Grenouilleau, president of ERB and leader of the Empreinte project.

The project ended in March 2022, allowing us to share initial feedback.

Thinking about the overall footprint of the habitat

The Empreinte project focused on four main areas of work: collective innovation, digital integration, the circular economy and the place of the inhabitant. It is thus the overall footprint of construction, construction sites and housing on the environment that has been redesigned.

“Innovation for innovation's sake has no interest in itself. We have ensured that the various opportunities opened up by digital technology, such as 3D reality or additive printing, or by the materials selected, make it possible to achieve an overall improvement in the footprint of the house on the environment, both in terms of waste management, energy consumption or its insertion into the neighborhood ecosystem” continues Thomas Grenouilleau.

For example, the construction site made it possible to test on-site industrialization: instead of manufacturing in the factory and assembling elsewhere, the robots came to the construction site to mount the walls in additive printing (3D printing). A technique which also makes it possible to limit the waste of material, calculated as closely as possible to needs.

The materials selection stage sought to favor proposals that met both the sustainable innovation approach and the needs established by the engineering studies. A pragmatic selection which has made it possible to bring together biosourced materials (clay, cork, wood, etc.) but also from the circular economy (aggregates, paint, etc.). The structure is made of PET foam from recycled bottles, in which low-carbon concrete has been poured.

A new stage for the construction revolution

This extraordinary construction site was first of all a laboratory, a field dedicated to the revolution that the construction sector must operate to stay in step with the challenges that are imposed on it. 20% of carbon emissions come from the sector, which has to deal with ever-increasing demand.

“ERB offered to make the Empreinte house available to us. We are thinking about making it a space dedicated to ecological transition and all the questions it raises. This seems to us to be in the continuity of the dynamic launched by the collective » says Yves Colliot, Mayor of Beaucouzé.

The solutions validated by this first project can now be isolated, to provide technological bricks that meet the problems of more conventional sites.

For Empreinte, the challenge now is to continue collective experimentation.

“To market the house or to redo it does not interest us. What we are looking for is to continue to do even better, to find new solutions to offer construction methods that are ever more positive for the environment, while being economically reasonable. The next goal we have is to deploy an additive printing solution for walls based on raw earth, excavated on site; potentially, this would bring together in one step digital technology, on-site industrialization, biosourced materials and circular economy while validating thermal insulation standards” enthuses Thomas Grenouilleau.

An innovation that would require about two years of R&D, for which the potential openings are already promising.