Post Headquarters - Helix
The new headquarters of POST Luxembourg redefines the role of corporate architecture in the city. Located at a key urban junction in Luxembourg’s Gare district, the project engages with its dense, fragmented context not through iconicity, but through continuity, dialogue, and responsibility.
Located in Luxembourg’s vibrant Gare district, the POST Luxembourg Headquarters brings together 1 000 employees within 22 370 m² of work, meeting, and public spaces. The project unites the restored heritage-listed Accinauto building with a new stone-clad structure, creating a strong yet balanced urban presence. Vertical stone fins lend rhythm and depth to the façade, while the central atrium and its spiral staircase foster communication and openness. Built with local materials and conceived to last, the building connects past and future, integrating naturally into the fabric of its dense urban context.
The project faced a complex brief: to create a spacious headquarters for a significant number of employees within Luxembourg’s dense Gare district, balancing heritage, a highly active urban context, and ambitious sustainability goals. Rather than pursuing a vertical landmark, the strategy focused on dialogue - between past and present, openness and restraint, city and workplace. By preserving and extending the heritage-listed Accinauto building, the design maintained continuity with its surroundings while minimizing demolition and carbon impact. Sustainable strategies, including reuse of existing structures, active tiles, heat recovery from the adjacent data center, rainwater recycling, and PV panels, enhanced environmental performance. Inside, a central atrium with a
spiral staircase structures the workspace and fosters openness, communication, and well-being. The result is a civic, sustainable building that mediates between vibrant surroundings and an interior defined by clarity, light, and calm.
The building is constructed with a reinforced concrete structure, while the façades combine wood-aluminium frames and vertical natural stone fins that provide rhythm, shading, and permanence.
Interior finishes alternate between natural stone, oak, and steel, creating a balanced and tactile atmosphere. From the outset, sustainability guided every decision: the reuse of existing foundations and structures saved over 8 600 m³ of concrete and nearly 2 600 t of CO₂, while local material sourcing reduced transport and emissions. Durable natural materials and modular façade systems ensure long-term resilience and low maintenance. Achieving a DGNB Platinum certification, the building was recognized for its exemplary performance across ecological, economic, socio-cultural, and technical criteria. As the first project outside Germany, it also received the DGNB Diamond distinction for outstanding design and architectural quality.
The façade
Framed within Luxembourg’s densest urban fabric, the façade of the POST Headquarters resolves a complex dialogue between heritage and modernity. Through the play of extrusion and morphing, the sloped roof of the historic Accinauto corner building gradually transforms into a vertical plane, aligning with the new stone façade and creating a continuous, unified frontage. This folding and rotation allows the contemporary building to transition gracefully from the historic streetscape, bridging Haussmannian heritage and modern urban rhythm. Vertical natural stone fins provide rhythm, depth, and solar protection while echoing the mineral permanence of the surroundings. Locally sourced stone and modular assembly ensure sustainability, durability, and precision. The façade is simultaneously monumental and permeable, anchored yet open, mediating between past and future, city and workplace, and redefining the corner as a civic and contemporary landmark.
The staircase
Post Luxembourg has an organizational structure built on clear communication between its various sectors. Accordingly, its headquarters was designed to support an open, horizontal hierarchy, connecting each department around a vast atrium that spans the full height of the interior. The central atrium provides a generous, light-filled space where a staircase unfolds in a sculptural manner, emphasizing the vibrancy of the workplace while fostering communication and openness.
The staircase rests on the ground floor and extends above the void, with its weight supported only on select landings. Remarkably, despite its cylindrical form and the fact that part of its weight is suspended, the structure remains completely stable, without any perceptible movement or vibration. This stability is largely due to the choice of steel as the primary material.
Ultimately, the staircase draws the eye and creates a striking impression with every visit, becoming the centerpiece of the atrium and a symbol of Post Luxembourg’s open, connected work environment.
The spiral staircase, rising 30 meters, is the defining feature of the 200 m² atrium and is constructed entirely of steel. Realizing this ambitious design required significant expertise and was made possible through the collaboration of Luxembourg-based Metaform, Ney & Partners, and MetallArt from Germany.
Sustainability
Achieving DGNB Platinum and Diamond certification, the most rigorous label for ecology and economy in user and environmentally friendly construction, creating a building with energy efficiency class A, thermal insulation class A, and an overall energy consumption of 118.9 kWh/m² per year required a series of precise and committed actions.
The project reused the existing foundations and basements, saving large amounts of concrete and materials while avoiding hundreds of truck trips in the heart of the Gare district. The conservation of the historic building and the construction of the new building on an existing foundation and basement structures saved over 8 600m³ of concrete. The project reportedly saved 2 600 tons in carbon dioxide emissions compared to what would have been released into the atmosphere if it were demolished and built a new one.
Local practices were prioritized through the use of local and European materials, a focus on heritage conservation, and the promotion of local craftsmanship. Every material used in the project was carefully inventoried, classified, and validated to ensure sustainability and efficiency.
The building structure is made of concrete, chosen for its strength and durability. Concrete is used in various parts of a building, including the foundation, walls, floors, and roof. The Helix building features a 2 736 m³ ice storage tank on the fourth basement level, divided into five interconnected chambers holding 2 133 m³ of water. Several kilometres of spiral-shaped tubing allow energy exchange between the water and the building’s heat pumps.
In winter, when primary energy from IT installations is insufficient, the heat pumps draw energy from the tank, gradually freezing the water and generating additional energy. In summer, the frozen tank acts as a natural cooling reservoir, providing air conditioning for the building. While small-scale ice storage exists in Luxembourg, typically in private homes, the Helix system is unique in its scale and ambition within the Greater Region.
The building also integrates multiple energy sources. The roof is equipped with 82 kWp PVT (photovoltaic-thermal) modules, producing electricity while capturing thermal energy from the air.
Air coolers recover energy when temperatures exceed five degrees, and additional energy comes from exchanges between the ice tank and the ground. Heat from the data centres and IT equipment of both the Helix building and the adjacent CT telecommunications centre is also recovered and incorporated into the energy concept.
Together, the solar modules, ice accumulator, and heat pumps create a highly efficient and cost-effective heating and cooling system that reduces energy use and avoids fossil fuels. Heating and cooling are delivered via an active slab system with pipes embedded in the concrete ceilings.
Rainwater is collected from the roofs and stored in a 270 m³ reservoir on the fifth basement level. It is pumped to toilets and urinals up to the third floor and used to irrigate terraces and the atrium, further enhancing the building’s sustainable operations. Other implemented strategies are, active tiles, night cooling or automated lighting management.
