Sideshore’s design builds upon the foundations and footprint of a 1980s structure that once housed one of Luxembourg’s major financial institutions—the Kredietbank Luxembourg (KBL). Rather than seeing the existing structure as a constraint, the design uses it to shape the building’s spatial logic. The resulting volume, Gemini One, reflects a commitment to sustainability and reuse: it is certified to the Passive House standard and holds an AAA energy rating. This approach reflects Sideshore’s ongoing interest in transformation, preservation and smart densification.

Gemini One is composed of three storeys below ground and five above, which are arranged around a vertical atrium illuminated naturally by skylights and expansive windows. Each of the above ground floors has a distinct footprint, creating an angular interplay of volumes that animate the central core and reshape the building’s circulation—removing the need for closed corridors.

The residential complex comprises nineteen loft-style apartments that range in size from 114-199 square meters with dramatic ceiling heights of between 3.45 and 3.8 meters. All consist of three bedrooms and a minimum of two bathrooms. The floorplan of the building uniquely eliminates direct adjacency between units to enhance privacy. Each apartment features windows across three aspects, maximising natural light while framing views across Bertrange. Spacious terraces and balconies invite the outdoors in, and select outdoor areas feature digitally operated bioclimatic pergolas for climate and light control. 

The lower levels retained from the original building have been transformed to host a suite of residential amenities. The former bank vaults have been converted into wine cellars, while a new wellness area features a 17-meter indoor pool, sauna, hammam, gym, dressing rooms and bathrooms. Additional facilities include secure bicycle storage with charging stations, as well as underground car parking equipped with electric vehicle chargers.

Gemini One demonstrates how disused commercial spaces—banks, offices, and roadside buildings—can be reimagined in new ways, offering a blueprint for future interventions in Luxembourg’s evolving urban fabric. As Carolina Lazo-Albrecht, Founder of Sideshore and Lead Architect on the project, notes: “Gemini One is in no way a standard building.”