It is on a 1.5 ha tenement located in Bron, in eastern Lyon, that the regional management of Léon Grosse has chosen to build its future. “We were already established on this site but we wanted to bring together all of our activities and our employees who had until now been dispersed throughout the Lyon metropolitan area,” recalls Rémi Hovaere, regional director of Building South. Having become the owner of the entire land, it was under the leadership of its Real Estate subsidiary that Léon Grosse launched a mixed program combining 5,000 m² of offices, a third of which for its own use, 85 housing units and two commercial units.
“Virtuous solutions”. In this rapidly changing Sept-Chemins district, the company has just delivered the first phase of this operation designed by the AA Group agency, the architect Corinne Lecuelle and the landscaper Anne Gardoni. Inaugurated on June 6, it includes the tertiary complex and two buildings totaling around thirty homes for home ownership. “From the start, we had the desire to bring this project called “Le 8e chemin” towards virtuous solutions within a work envelope of €23 million”, testifies Patrick Verdier-Farudja, real estate director Rhône-Alpes Bourgogne.
Among the construction solutions chosen, Léon Grosse Construction, in charge of the work, implemented a very low carbon concrete developed by Vicat. Some 830 m3 of Carat concrete were thus poured to make the floors of part of the offices. “For the exterior walls of the bicycle shed, we experimented with earth concrete, and for the partition walls, our teams laid rammed earth blocks manufactured in a factory located less than 10 km away”, illustrates Rémi Hovaere. The earth used for the rammed earth comes from the quarries of Saint-Pierre-de-Chandieu located 20 km away.
“Improved energy component”. Drawing on the expertise of two recently acquired companies – Voé (geothermal and biomass boilers) and Sunopée (photovoltaic) – and on the group’s low-carbon strategy, “we have improved the energy aspect of the project,” says Patrick Verdier-Farudja. Thus, to ensure the production of cold and heat, a geothermal heat pump system (44 deep wells of 160 meters) was chosen. On the car park, a shade covered with photovoltaic panels (450 m²) will produce 110 kWh/year to power the pumps.
Finally, the reuse component was pushed forward with 6 t of materials collected on the site for the Solidarity Reuse Hall in Rillieux-la-Pape and 7 t recycled by the Minéka platform (Villeurbanne). “We are also going to experiment with this process with structural concrete by cutting 20 linear meters of retaining walls from an existing building to be demolished in order to reuse them for the same purpose at the level of the underground car park common to the offices and the remaining housing. build,” adds Rémi Hovaere.
