[Avant-après] What will the Tour Bretagne look like tomorrow?

Built in the vertical euphoria of the Trente-Glorieuses, this 144 m high building, including 32 levels of offices, had to close its doors and its famous Nest in 2020. Emptied of its occupants after in particular the discovery of asbestos, the “Nantes skyscraper” has since been dormant. Not for long! Four years after its closure, the building, which, due to its size, can be seen for miles around, is preparing its comeback with a complete renovation and a new look.

The Giboire real estate group, main owner of the building, and the architects of the PCA-Stream and Magnum agencies, chosen to carry out its transformation, presented their project on Thursday, November 21, in the presence of Johanna Rolland, mayor of Nantes and president of Nantes. Metropolis.

The virtuous reconversion of an urban wasteland

« Created in the 1970s to accommodate offices, this tower is today an urban wasteland in the city center, and more pollutedrecalls Johanna Rolland. These are all free square meters that we can reconvert to repair the city and rebuild it on itself in accordance with ecological imperatives. » In the body of the rehabilitated tower, the offices from the 1970s will be transformed into around 200 housing units, spread over 30 levels and mostly equipped with loggias. And this is far from the only expected change! “ This project is a unique opportunity to turn the page on the energy-consuming tower of the 1970s but also the opportunity to profoundly improve public spaces, to sew the link between the upper town (Graslin) and the lower town (Bouffay) and to make more room for vegetation », Continues the mayor of Nantes.

A clear and slender silhouette

On the design side, the Tower will abandon its dark and brown appearance to adopt a clear silhouette, “ sober and elegant ». « We chose a lightweight façade material – recycled aluminum – whose color will change depending on the orientation and brightness. », says Philippe Chiambaretta, PCA-Stream architect. “ The people of Nantes have an ambivalent attachment, made of I love you neither, but this tower, the fruit of a bygone era, remains a real urban marker for Nanteshe observes To bring it back to life and fight against the obsolescence of buildings, we have imagined a restructuring adapted to the challenges of our time. » The architectural intervention will be “ frugal, eco-responsible and far from free gesture », he promises. The idea is not to make a clean slate of the past. “ Its original shape will be preserved while respecting its history and its spirit, but we will reinforce its slender side to enhance this emblematic building. »

A reduced carbon footprint

Sobriety is at the heart of the project. “ The objective is to make the Tour Bretagne an exemplary rehabilitation operation in terms of ecology and land preservation.assures Michel Giboire, president of the real estate group. Choosing rehabilitation rather than demolition/reconstruction will save 14,000 m³ of concrete and 1,600 tonnes of steel, i.e. a carbon saving equivalent to 7,000 tonnes of CO2. » This represents 32,000 million kilometers by car avoided, or the annual carbon impact of 875 French people, according to figures from the Ministry of Ecological Transition. To achieve this, the Giboire Group is banking on the reuse of 100% of the materials resulting from the rehabilitation (166 tonnes are likely to be reused), a bioclimatic design, the use of eco-materials and an intelligent use of natural resources (sun , wind, rain and plant cover).

« The ambition is to eliminate the use of all fossil fuels, thanks to the connection of the Tower, which is today a thermal sieve, to the urban heating network of Nantes Métropole, 84% powered by local renewable and recovery energies. (biomass and waste incineration)specifies Benoît Garnier, architect at the Magnum agency. We have also worked on a design of the facade that is as optimized as possible with regard to energy consumption, particularly concerning the glass surfaces. “. An innovative heat production system, based on the recovery of hot and cold between the different occupants of the Tower, will be put in place. And the group is studying the possibility of producing part of the hot water needs by using the heat from gray water in housing and the hotel.

Shops, 250 bicycle spaces and premises for local projects

Designed as two distinct but inseparable buildings, the rehabilitation project will accommodate more diversified uses and in line with the challenges of the 21^e century. In addition to housing, the base of the Tower will house some shops, a co-working space, as well as a vast space of 1,000 m² which will host, at the request of Nantes Métropole and the City, local projects and activities. of social utility. The Breton Cultural Agency (ACB44) is already planning to develop the Kejadenn project (“meeting” in Breton) there. And the Ecossolies association new premises dedicated to the social and solidarity economy. Originally equipped with six car parks, the building will also tomorrow make more room for non-polluting mobility. The current five levels of parking will be recomposed to accommodate more than 250 bicycle spaces, and 160 spaces for cars (i.e. half as many as today).

A hotel, a restaurant and refuges for biodiversity

Another new feature: along rue de l’Arche-Sèche, a new building will adorn the foot of the building. There, in place of the Tower’s private underground car park, there will be a four-star Green Key hotel with around 100 rooms and a restaurant whose terrace, overlooking the roofs of Nantes, will be open to the general public. The surrounding public spaces will also be revisited in order to recreate pleasant circulation and wandering and give more space to nature. Along this building, a public staircase will be created to connect rue de l’Arche-Sèche to rue du Pont-Sauvetout. “ This will bring the Place du Cirque and Rue de l’Arche-Sèche area to full life. », specifies Johanna Rolland.

Now completely mineral, the project also plans numerous developments to promote biodiversity, which is currently non-existent on the site. Several roofs will be greened and the facade of the hotel will be decorated with climbing plants and nesting boxes for birds and beetles. Refuges are even planned on the roofs to accommodate peregrine falcons!

A terrace to enjoy the Nantes sky

Last, highly anticipated announcement, and not the least: “ Nantes residents will regain access to the top of the Tower where they will be able to admire the Nantes sky », welcomes Johanna Rolland. In accordance with the wishes of the mayor of Nantes, the 33^e et 34^e floors, freed from the current technical premises, will house a convivial and cultural “rooftop” place, as was Le Nid, as well as a panoramic belvedere rising more than 107 m above Place de Bretagne. And good news, this place offering a 360-degree view will be open to everyone. And accessible for free », reveals Johanna Rolland.

We will have to wait a little longer for the Tour Bretagne to reveal its new face. This very large-scale project will take several years. A first phase of work will be carried out in 2025 to clean and remove asbestos from the existing building. Then will come the rehabilitation and extension work of the whole. See you in 2029 to discover the new Nantes horizon (the skyline, some would say) and enjoy the most beautiful view of the city of the Dukes, the metropolis and the Loire estuary!

Also read:
Tour Brittany: story of an unloved woman, symbol of a bygone era

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