A groundbreaking housing rehabilitation project in Villiers-le-Bel, France, has successfully transformed a deteriorating 1970s condominium complex into a modern, energy-efficient residential development. The Pré de l'Enclos 2 Housing Rehabilitation, completed in 2024 by SOL Architecture & Urbanisme, demonstrates how innovative design and community participation can address both the housing crisis and energy transition challenges facing France today.
The project involved the complete renovation of a 91-unit condominium building constructed in the 1970s that had fallen into both technical and social decline. Spanning 7,500 square meters, the rehabilitation was carried out under France's Plan de Sauvegarde des Copropriétés Dégradées, a national program designed to support the regeneration of distressed private housing developments. The architectural team, led by Hélène Reinhard and Anne Maréchal, worked in partnership with engineering consultants Soliha, MEP specialists BE Alterea, and general contractor GTM.
The innovative design concept, known as "The Winter Gardens," created a revolutionary approach to thermal retrofit by expanding each dwelling with an inhabited layer between indoor and outdoor spaces. Rather than simply adding insulation, the architects transformed what would have been a basic insulation line into livable space, creating bright and adaptable rooms that significantly enhance comfort and daily life for residents. This approach converted former micro-balconies into insulated alcoves, effectively eliminating thermal bridges while extending main balconies into enclosed semi-outdoor rooms.
The rehabilitation process was notably participatory, with all 91 co-owners serving as both clients and active participants in shaping design decisions, from overall concepts to specific color palettes. SOL's team initiated the project with comprehensive door-to-door diagnostics to meet each resident individually, ensuring that every voice was heard, including those typically absent from formal meetings. This collaborative approach meant that construction became a continuous dialogue rather than a disruptive process, carried out in occupied conditions over two and a half years.
The technical improvements went far beyond traditional renovation measures. The project incorporated new windows, external rock-wool insulation, floor insulation, and upgraded ventilation systems. However, the most innovative aspect was using space itself as an energy device. The Winter Gardens function as thermal buffers during winter months and open thresholds during summer, allowing residents to literally occupy what was once the building's insulating envelope, filling these spaces with plants, furniture, and daily activities.
The aesthetic transformation was equally dramatic, with new extensions wrapped in blue mosaic tiles chosen collectively by residents for their tactile quality and cultural resonance. These tiles evoke both Mediterranean craft traditions and urban refinement, with unified color choices across the three buildings affirming a shared community identity. As residents expressed it, "We're one group, one entity."
The project achieved remarkable energy efficiency results, reducing energy consumption by 56 percent and reaching primary energy levels of 72 kWh per square meter per year, which is comparable to new-build standards. This dramatic improvement demonstrates that rehabilitation can achieve performance levels previously thought possible only through new construction.
Photographer Clément Guillaume documented the transformation, capturing how the rehabilitation turned necessary thermal improvements into architectural opportunities that enhanced both individual living spaces and community identity. The project shows how existing housing stock can become a field of renewal through thoughtful design intervention.
Pré de l'Enclos 2 represents a new paradigm in housing rehabilitation, proving that renovation projects can be as architecturally significant as new construction. The project demonstrates that rehabilitation is not merely a technical fix but represents the future of architecture itself – an architecture of transformation rather than replacement, where design excellence, energy performance, and community participation converge to dramatically improve daily life for residents while addressing broader environmental and social challenges.
