Lightwell: A Union of Past and Present

Redeveloped by Barthélémy Griño, Lightwell is an office building in Puteaux, one of the communes that make up Paris’s La Défense business district. Originally built in 1986 and named Galilée, the building has undergone a radical transformation under the ownership of Unibail-Rodamco-Westfield aimed at enhancing the existing structure through a sustainable and user-centric approach.

Lightwell: Renovated architecture in Île-de-France

Combining lacquered aluminum cladding panels and extensive glazing, the façade of this ten-story building retains the rhythm of the existing structure while allowing abundant natural light to enter inside.

One of the key elements of the transformation is the expansion of office spaces. The northwestern façade was moved forward 2.5 m, creating a linear, open, and fully glazed frontage on the Esplanade, La Défense’s extensive pedestrian zone. A mezzanine level added to the top floor created even more new floor space.

The project included the complete redesign of the building’s entrances to improve the connection with the surrounding public spaces, including the Esplanade and Cours Michelet.

Outside, the design team remodeled the arcades to bring vitality and functionality back to the heart of this city block. Inside, the project introduced an internal street and monumental atrium that traverse the entire building, adding further to the level of natural light inside.

Flexible, functional workspaces

New features, including the transformation of the atrium staircase into a tiered area, have created spaces for informal discussions and exchange.

The workspaces are complemented by a series of services intended to improve staff well-being, including a business center with a modular auditorium, a sports and wellness area, a company restaurant, and an accessible green roof with panoramic views of the city.

A feature of many levels, planted terraces create a local ecosystem with cool islands and places where users can connect with nature.

An example of urban sustainability

The project left two-thirds of the existing structure intact, therefore minimizing both waste and environmental impact. All the demolished concrete was recycled into new material, while 88% of the construction waste was also reused. Finally, 21 metric tons of stone from dismantling the old façade was recovered and transformed into terrazzo flooring for the lobby.

Designed to achieve HQE Exceptional and BREEAM Excellent certifications, Lightwell stands out for the use of bio-sustainable materials, such as timber, and local resources. This resulted in a 30% reduction in carbon emissions compared to constructing a new building in a less central area.

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