Rugo, Luxemburg

Rugo Building – Luxembourg
Project overview

The Rugo building is an office development in Luxembourg that underwent a façade retrofit to improve energy performance and occupant comfort. The refurbishment was led by Ballini, Pitt + Partners, and commissioned by Becolux Investment. The building now features a distinctive double‑skin façade with curved glass.
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Design challenge

The existing façade lacked effective solar control and suffered from moisture problems within the cavity. The new design needed to accommodate curved outer glass panels and ensure that condensation did not accumulate inside the cavity. The shading system had to be segmented to match the curvature and allow maintenance of the blinds.

RetroSolar strategy

The retrofit introduced RETROFlex blinds within a non‑ventilated double‑skin façade
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. The inner façade is segmented, and the blinds are segmented accordingly to align with the curved outer glass. Operable windows are included on the inner façade to allow maintenance and to manage humidity. Fresnel optics ensure that the blinds redirect light without creating glare. The segmentation also helps manage vapour diffusion and prevent condensation.

Building physics and performance

The retro‑reflective blinds reflect solar radiation before it enters the cavity, reducing heat gain and improving thermal comfort. The segmentation and operable inner windows allow the cavity to be accessed for maintenance and moisture control. The curved outer glass creates a unique façade expression while the blinds maintain consistent optical performance across the curve. The combination of curved glass and retro‑reflective shading demonstrates the versatility of the technology.

Architectural outcome and significance

The Rugo building is a striking example of a retrofitted façade that pairs contemporary aesthetics with high performance. The curved glass and segmented blinds create a dynamic façade that catches and reflects light throughout the day. The project illustrates how retro‑reflective technology can be adapted to complex geometries and highlights the importance of managing moisture in double‑skin façades.