PROJECT DETAILS
Context: A Landmark Gateway to the City
At the threshold of the EuroRennes district, the southern entrance to the Rennes metropolitan area is completing its transformation as part of an ambitious urban regeneration scheme. Visibility was therefore a key factor for developments in the area — especially for the office project located on this 2,000 m² plot bordering the ring road and just steps from the Alma shopping centre. Selected by landowner Unibail-Rodamco Westfield for its vision and commitment to architectural quality, OCDL Groupe Giboire chose, following a design competition, the proposal submitted by architecture firm 2A Design.
“We were impressed by how the project responded to the urban brief set out by the City of Rennes — to create a landmark, a signal at the southern gateway to the city,” explain Alexandre Racine and Xavier Leseur, Programme Director and Production Director at OCDL Groupe Giboire. The resulting building takes full advantage of the triangular shape of the site, rising 6,250 m² over nine levels (ground floor + 8), crowned by a metal superstructure that gives it the appearance of a jewel on the Rennes skyline.
Challenges: Aesthetics and Performance
Named Emergence, the building forms a striking new landmark on the urban horizon. Its trapezoid shape, along with façades of dark aluminium and transparent glass, suggest a diamond. The building appears to be split into two volumes: the first, covering the first and second floors, floats above a fully glazed base facing a landscaped forecourt; the second, from the fourth to the eighth floors, seems to defy gravity above the third floor — which acts as a glazed fault line — and rises behind a metallic mesh screen topped with a rooftop superstructure.
Beyond its visual impact, this glass-and-metal envelope protects an internal layout that is relatively “simple”, built around a central core to facilitate flexible subdivision. For both investors and future occupants, the building offers high performance in terms of energy efficiency, thermal comfort, and acoustics — thanks in part to WICONA solutions implemented by Aluvair.
WICONA Solutions: Exceptional Flexibility
The ground floor and third floor are defined by transparent, faceted façades featuring large glazed panels and complex angles of 10° (5° on either side of each spine). The base of the building is fitted with a WICTEC 60 grille curtain wall, capable of supporting glazing sized 1,800 mm wide by 4,500 mm high. On the third floor, a WICTEC 50 grille curtain wall takes over at a lower height.
Another distinctive feature is the framed façade spanning the fourth to eighth floors. Based on large-format WICLINE 65 concealed-sash profiles (panels of 1,790 mm wide × 3,240 or 4,485 mm high depending on the level), this façade is set behind the decorative external metal structure, which also functions as a sunshade. A full-size prototype (4.5 m per side) was validated on-site. Off-site prefabrication of the framed façade and the superstructure helped speed up and secure the installation process.
On the first and second floors, the same WICLINE 65 concealed-sash windows wrap around the building in continuous bands measuring 2,800 or 2,350 mm high, alternating one openable unit (with spandrel or transom) and one fixed panel, each 900 mm wide.
In terms of performance, the WICONA systems include acoustic glazing rated between 30 and 36 dB depending on the façade, and solar control glazing on both south-facing façades. The dark black (RAL 9005) finish of the aluminium frames and metal superstructure, with 30% gloss, completes the building’s dark diamond-like appearance.
