First building of the future Polaris District by LAN Architecture

Description of project by LAN Architecture

The development of the Brossette site completes the transformation of the Boulevard Vincent-Gâche, with the largest project ever built on the Île de Nantes. This island, formerly an industrial zone of warehouses belonging to the manufacturer of lavatory components, this 1.5 hectare lot facing the Loire River, will soon be home to a total of six new buildings, with mixed-use programs, including a panoramic 18-story tower, delivered in April 2018.

Convinced of the inefficacy of the principle of restrictive specifications briefs (typical of ‘ZACs’ of joint development zones) in the urban fabric, the project, the outcome of a competition, proposes a new method. Integrated into the continuity of the work of the UAPS (authority in charge of the urban development of the Île de Nantes), LAN originated from the design of a master plan and the grand urban principles underpinning this project, and with the office as the lead contractor of a consortium of architects who have worked on this ensemble in order to adjust forms and dimensions able to house the program while strengthening the design of the public space.

In parallel, the effort to imbue the neighborhood with a genuine identity is manifested in a jointly decided definition: to imagine the occupation of spaces, establish a relationship between the potential size and the façades, study the prevailing winds and sunlight, are all subjects analyzed together to ensure a coherent urban result.

The site is at the intersection of several formal systems: buildings dating from the 1970s condominiums based on the model of large housing projects or “estates,” an office complex with courtyards and gardens which was never entirely completed and the intervention of Alexandre Chemetoff, architect of the first phase of the islands urban renewal.

This heterogeneous context called for an approach bringing greater cohesion, as proposed by Anne-Mie Depuydt  and Marcel Smets, the urban planners in charge of the Île de Nantes. Thus, the new buildings enclose the public space by creating fronts. The buildings are laid out based on a system of strips; they cross the site from one end to the other and offer new pathways to place the core area in tension with the banks of the river.

The interior areas created by the buildings emerge and are organized into squares, forecourts, terraces and gardens, thereby enhancing the range of uses based on specific themes, according to the requirements of the public space.

Despite the fact this lot is entirely privately owned, all the outdoor spaces are open to the city. The district having become an entirely pedestrian zone is traversed by a central avenue; the backbone of the island, it leads to the core area of the project : a broad plaza in front of the tower, now renamed the “360° View”, will become a public plaza ceded to the city. Here, four enormous polar trees dialog with the façade clad in brushed aluminum. It reflects its surroundings in daylight and enlivens the plaza at night in the interplay of sidelights with the perforated shutters. Viewed from the south, the building closes the perspective.

From the north, and the river, it sets the tone of the development. At the foot of the tower, Polaris is home to a vast campus, slightly more than 3,000 m2, in which the Vatel international school of hotel management and tourism chose to place its new site. It includes classrooms, a restaurant, a brasserie and a café open to the public, as well as a residence-service for students with 300 apartments.

The program also includes an additional 250 apartments and 6,500 m2 of office space and 600 m2 of shops distributed among the different plots of the development. In addition to the alignment of the floors from one building to the next, and they share the regularity of the openings of the façades; each shared space – regardless of its position on the site of the building to which it belongs – come together on the same level, the one offering an unobstructed view of the skyline of the older center city in the distance.

The Polaris city block

The urban project is based on the theory that the identity of a city emanates from its urban forms. The Brossette city block comprised of two contrasting formal systems, on one hand the courtyards and garden, on the other the great housing estates, must achieve a synthesis of these two models, in a way that establishes continuity and creates harmonious interconnections.

The public space

This operation includes the design of 6 buildings and the public spaces. The challenge resides more in the definition of the voids than in the characterization of the volumes. The core of the project is imagined as negative space in the form of a fault: an empty space that one penetrates, and which is designed to serve the other spaces by enhancing the value in terms of light, comfort, wellbeing and functionality.

The 360° View Tower

The 360° View Tower represents the end and the beginning of the Brossette block. Seen from the Loire River, its volume heralds all the elements that will be developed thereafter across the site. Conversely, when viewed from the south, this architecture will complete a succession of spaces and connections that will give the Brossette city block its character.

The net volume imagined in the beginning very quickly had to be enlarged and adjusted. This involved a design that took into account the trees, the perspective from the main axis of the site, the dialog with the system of variable heights of the other buildings and its role as a signal.

It contains 79 apartments as well as commercial space on the ground floor. It is located on the northern end of the lot at the corner of the Boulevard G. Doumergue and the Rue F. Albert. Located on the axis of the Brossette courtyards, the building is the northern edge of the Place Brossette. It stands parallel to the Boulevard G. Doumergue with a setback from the public space ranging from 7 meters to 3 meters (at the intersection of G. Doumergue and F. Albert). On the Rue F. Albert, the building has a setback of 11 meters to 4 meters from the streets (at the intersection of G. Doumergue and F. Albert). The volume is placed in alignment with the Brossette public space.

A commercial space is located at the corner of Boulevard G. Doumergue and Rue F. Albert. This space has a usable surface area of 235 m2, and will take advantage of its privileged position between the quays of the Loire and the Place Brossette to enliven the base of the tower and the adjacent public spaces.

The upper floors (G+1 to G+18) contain apartments ranging in size from 1 to 4 bedrooms. The largest apartments take up the upper floors with duplex apartments occupying the top floors (G+17-G+18). The building’s structure (stress-bearing façade + column and beam) allows for great flexibility in floorplans, the distribution of typologies being adaptable according to the requirements of future buyers. The floor space dedicated to the housing part of the program amounts to 4,821 m2 of usable floor space.

The building is the highest of all those comprising the Brossette city block, culminating at 55 meters with 18 stories above the ground floor.

The building takes full advantage of its height, opening broadly onto its context and especially onto the Loire River and the city’s historic center.

This building serves as a signal for the development. Its form is composed of three strata: the base (Ground-G+6), the intermediate layer (G+7-G+8), the emergent part (G+9-G+18). The intermediate level and the emergent part are set back, offering spacious private terraces overlooking this privileged context. The volume narrows as it rises, echoing the polar trees beside it. Each shift in volume corresponds to the height of neighboring buildings, harmonizing its relationship among these variations.

Benefiting from its exceptional location on banks of the Loire, 84% of the apartments offer views overlooking the river, the remaining part (16%) being oriented in a southerly direction overlooking the Place Brossette.

Materiality

The smooth brushed aluminum façade gives the building a unified look while capturing the reflections of its context. At night the interplay is inverted and the building is enlivened by the varying uses inside glimpsed through the perforations of the cladding. These also serve to manage the apartments’ exposure to sunshine.

Shutters

The façade is composed of a regular horizontal framework applied to all four façades. The design of this framework is imagined from the interior of the apartments to offer framed panoramic views that take full advantage of the tower’s height and the quality of the context (The Loire River, the historic town center, the Île de Nantes). The magnificent perspectives are accentuated by the high and low windows.

The concrete stress-bearing façade is covered in an exterior insulation of mineral wool with a brushed aluminum cladding mechanically fixed to a secondary metal frame.

The framework of the façade is composed of these solid, horizontal and vertical strips alternating with perforated parts in front of the joinery. The perforated sheet metal is fixed to the front of the lower window, and slides in front of the upper one. The perforated shutter slides vertically (one part upward and one part downward) behind the unperforated aluminum plates.

Framed views

Standing beside the Loire River, the tower rises to a height of 18 floors. The arrangement of the façades from the outside composed of windows on each level, distorts the scale. Inside the apartments, panoramic windows offer vantage points overlooking the Loire and surroundings.

Apartments

Most of the apartments benefit from spacious loggias, extending living areas toward the outside. The flooring of the loggias is composed of poured concrete, whereas the vertical partitions are covered in light gray plaster. The joinery, hidden behind the cladding, is in light gray PVC.

The fixed cladding and the sliding shutters guarantee the privacy of loggias and offer protection from the wind (especially in the apartments on the upper floors).

The Loggias

Each apartment is organized around a large loggia, a genuine extension of the interior living space toward the outside. In summer, these loggias help ensure ventilation of the apartments. They are set back from one floor to the next.