NGE contributes to the industrial revival of the former Canson-Montgolfier site in Annonay (Ardèche) with the construction of a new factory

Located on the former Canson industrial site, a new paper mill is being built in Annonay, Ardèche. This €7 million private industrial project, led by NGE on behalf of MP Hygiène-MPH1865, is part of a circular economy approach. Its objective is to transform waste paper into recycled paper, while simultaneously revitalizing a landmark site in the French paper industry.

Started in late 2022 and lasting nearly two and a half years, the project involves the construction of a new industrial unit integrated into an existing site, going far beyond a simple extension. NGE GC, the project manager, is carrying out all the civil engineering work alongside NGE FONDATIONS for the foundations, GUINTOLI for the earthworks and infrastructure, and ERCM for the steel structure. The completion of the project marks a major milestone in the site's industrial continuity.

The factory comprises three adjoining buildings, each dedicated to a specific stage of the papermaking process: the Pulper building, the Drum building, and a third, more complex building, constructed on 8-meter-high stilts due to the immediate proximity of the Déôme, a stream running alongside the site. This construction method allows the factory to meet significant hydraulic constraints in an environment subject to heightened environmental monitoring, without any direct discharge into the natural environment.

The structures, made entirely of concrete with a metal frame roof on the stilts, were fully dimensioned according to the industrial process defined by Toscotec, an Italian specialist in papermaking equipment. The differences in volume and structure between the buildings are not due to architectural choices, but to strictly industrial requirements. NGE GC thus carried out a custom civil engineering project, perfectly adapted to the installation of the equipment (particularly the tanks), networks, and fluids.

The building on stilts represents the greatest technical complexity of the project. It is based on a post-beam-slab system, with beams entirely prefabricated off-site.

The integration of drainage networks directly into the slabs required particularly precise design and execution work, in order to allow the passage of the networks through the beams without compromising their structural resistance.

The construction project was also marked by a major climatic event, with an exceptional flood in October 2024 that temporarily submerged the site, reinforcing the requirements for coordination and responsiveness of the teams.

According to Michel CHARROIN, director of major industrial projects: "This project embodies the reindustrialization of the region and NGE's ability to transform a historic site into a high-performing industrial facility. It is an achievement serving the local economy and sustainable industry."

According to Arnaud DIDION, agency director at NGE GC: “This project was particularly demanding, both due to its industrial context and the site's environmental constraints. Building a new unit on a former site, with a building on stilts on the banks of a river and a highly constrained industrial process, required a great deal of rigor and adaptability. It's a project the teams can be proud of, because it combines technical expertise, responsiveness, and concrete industrial utility.”