ARCHITECTURE FIRM A26 SIGNS FIRST BUILDING IN 100% RECYCLED CONCRETE

In Gennevilliers (92), landlords Seqens, the Holcim Group, Legendre and A26 have just signed a world first: the construction of a 76-unit social housing complex using entirely recycled concrete.

Credits: Mickaël Bouton for A26

At first glance, this classic demolition-rebuilding operation carried out in Gennevilliers on behalf of social landlord Seqens seems rather conventional. In reality, the 'Recygénie' residence is a model of low-carbon construction that combines innovation, sustainable development and short supply chains.

According to the companies involved, the 76-unit social housing complex is the first building in the world to be made from 100% recycled concrete. The clinker was produced by reusing 11 types of industrial waste. The rubble and sand came in part from the demolition of the old buildings occupying the plot. Even the water used was recycled, coming directly from the cleaning water of the concrete plant and rainwater.

After winning the competition and applying for planning permission for the residence, we were asked by Sequens and the Lafarge group to reinforce the environmental aspect of the project by using 100% recycled concrete. A specific ATEx was then applied for and obtained from the CSTB to guarantee compliance with construction standards.

"We estimate that this initiative will save almost 3,000 tonnes of natural resources," says Elliott Laffitte, President of A26 and a participant in the project. "We're very proud to have taken part in this unprecedented project, which demonstrates our ability to reconcile urban development with environmental performance.

Credits: Mickaël Bouton for A26

By replacing old, dilapidated buildings on a plot that had already been developed, the 'Recygénie' residence is also fully in line with the land-saving objectives of the French Climate and Resilience Act.

Demolition of the existing bar was completed in 2021, and construction work on the new residence began in December 2022, with completion scheduled for the end of 2024. In total, the construction of the 'Recygénie' residence will have represented an investment of around 9 million euros.

Marion Oechsli, Managing Director of Seqens, comments: "This unprecedented partnership with Holcim has enabled us to implement a totally innovative recycled concrete technology, perfectly in line with the Group's climate strategy. It's the fruit of unprecedented teamwork, in line with our CSR and reuse policies. We can only hope that this operation will inspire other players in the construction industry to raise their level of ambition when it comes to recycled concrete."

Credits: Mickaël Bouton for A26