2018 - 2024

Construction of a mixed-use project rue de Hollerith in Luxembourg including offices, housing, retail and public plaza (work in progress)

  • passive
  • residential
  • office
  • equipment
  • refurbishment
  • new build
Rue de Hollerich 19-23 1741 Luxembourg
Structural engineering
Services engineer
13 995 sqm above ground level
n/c € htva

Complete description

Developed with clients IKO REAL ESTATE and THOMAS&PIRON LUXEMBOURG following an international call for projects, UNICITY in central Luxembourg city concentrates 8720 sqm of offices, 4720 sqm of housing and 471 sqm of retail on an oblong site bordering a 20th century quartier at one extremity, and a 21st century soon-to come real-estate development on the other. From the onset the project focuses on reciprocity, devoting 40% of its plot to unbuilt zones two-thirds of which form publicly accessed plaza, and connecting with the skyline with extensive rooftop terrasses for both offices and housing. In short a design specifically targeting interaction with existing and future surroundings, articulating the bits and pieces of the fragmented city-scape it is embedded in.

Purposely therefore unbuilt space is positioned on the site’s busiest corner where pedestrian traffic is at its most intense. Two new volumes organize site massing. Arriving on site from the train station west housing first diligently extends the rue de Hollerich’s existing street alignment, dressing the entirety of the grey and gloomy unadorned party wall currently looming over the site. At upper floors exuberant terraces are scooped out of its slanted rooftops, but elsewhere the understated form deliberately cedes prominence to the continuous retail ground floor it floats above. The plaza guides occupants and visitors upwards along its animated string of shops, cafés and restaurants level with the open areas they are destined to interact with, characterized by staggered swaths of gently sloping stone completed with benches, low-lying vegetation and fast-growing trees for welcoming shade.

Next, pedestrians reaching the plaza’s high point arrive at the threshold of the existing 1930’s facades maintained at City Authorities’ request, above which the second principal volume emerges. The latter contains offices at upper levels, and below retail and housing lodged behind the carefully restored modernist brick facades, with their robust horizontals and delicate brickwork inspiring in part the projected facades. Entrances to flats are unmistakably positioned on the plaza and clearly visible with their original detailing. Entering the main building through the center of one of these preserved facades, a wide passageway generously carved out of the ground floor opens up before us, joining the bright and busy plaza left behind with the soon-to-come bustling Wurth neighborhood ahead. The ambiance here is light, airy, a high-ceilinged shortcut leading to UNICITY’s north entrance, destined in years to come to rise in prominence as the new territory beyond develops. This undulating dilating interval federates on all fronts, leading to diverse shared functions and vertical circulation routes inside, and hooking up old and new parts of the city outside. Neutrally staged as uncluttered space inviting to stroll through, or linger in, connecting midway with a 5-story atrium protected from rain and cold by a glass roof flooding this flowing pedestrian-only interface and all floors above it with natural daylight. On upper floors exuberant inside-out dialogues are further implemented by the way of large stepped-back rooftops serving as extensions of the partitioned or open-plan layouts proposed, with extensive planting and outdoor furniture geared for informal work, open-air breaks and lunchtime gatherings.

The fluidity strived for here touches all design aspects, even angles get rounded off in order to instill smooth transitions from one plane to another, from one street to the next, or from one unbuilt space to the following. For offices continuous skins are clad with floor-height façade elements forming horizontal strata flowing under and above each other, wrapped in an all-encompassing made-to-measure metallic mesh for sun-protection. Housing is cloaked in a unique, singular pattern of softly glowing glazed bricks gliding all the way up to cornice level. And finally, sustainability and heritage issues equally impact design, resulting in modular, flexible layouts for all functions, energy efficiency, lightweight timber panels, extensive prefabrication and careful material choosing such as wood, terracotta and locally resourced stone.