The newly completed extension of a nursery school in Montfermeil by Paris-based practice Bien Urbain features a unique gill-like roof design, folded into four north-facing sheds described as gills. This 745-square-meter (8,019 sq ft) addition, completed in March 2026, harmonizes with the heritage-rich town center of Seine-Saint-Denis, steps from the Château des Cèdres and the church of Saint-Pierre – Saint-Paul. The roof’s design ingeniously draws light and air into classrooms without rising above the existing school’s ridgeline.
Mastering the Gill-like Roof Design
Situated in a historic setting, the extension respects the surroundings, including the Musée du Travail – Charles Peyre. Bien Urbain emphasized precision and functionality, integrating the new structure with existing floor levels and ensuring the two-story addition does not surpass the current roof’s height.
The innovative roof design’s focus on integrating aesthetics with functionality complements Go Architecture’s focus on practical design tools, which also highlights the importance of practical and modern architecture in educational settings.

The project innovatively adapts a double-pitch roof system to create four gill-like sheds that maximize light and natural ventilation, aligning the design with recent European school projects like MET Architects’ work in Basel. These structures direct daylight and air while protective overhangs shield the western facade and align with existing gutter lines.

Functionally, the extension connects two courtyards, offering a communal ground level with features like a northeast-oriented dormitory, distinct children’s toilet space, and a multipurpose room opening onto the courtyard. This allows for enhanced interaction and usability.

On the upper floor, the layout includes three classrooms facing the west courtyard and a library to the north. The compact design fosters architectural and ecological efficiency while a landscaped strip along rue de l’Église offers a natural boundary and complements the nearby Arboretum park.

Vassens stone clads the exterior, sourced from a quarry an hour and a half away, drawing continuity between the extension and historical masonry nearby. This approach ensures the extension resonates with its architectural surroundings.

Aesthetically minimalist, the interior features protected timber structures to minimize carbon footprint, leaving some areas exposed for visual warmth. The zinc roof and expansive clear glass facades enhance fluid transitions to outdoor spaces.

A covered walkway connects the new extension to the existing building, providing shade and continuity, much like Boman’s work in Nanteuil., capturing the dynamic interaction of light and space, highlighting the design’s intent for natural integration.

Michel’s expertise extends to photographing iconic French heritage sites, showcasing spatial rigor in his work. His portfolio is available for viewing on Instagram, reflecting his commitment to architectural photography.

The existing 1,242-square-meter (13,369 sq ft) building underwent a careful insulation retrofit to maintain its historical facade. This thoughtful approach allows the building to visually express its evolution without disrupting its architectural narrative.

From rue de l’Église, the extension remains subtle, with its stone facade concealing the innovative design. The orientation towards the active courtyard optimizes functionality and aesthetic quietly and effectively.
Sources & Links
Source: urdesignmag.com
Frequently asked questions
What is unique about the nursery’s roof design?
The extension features a gill-like roof design, folded into four north-facing sheds described as gills. This design ingeniously draws light and air into classrooms without rising above the existing school’s ridgeline.
How does the extension respect its historical setting?
The extension respects its surroundings by harmonizing with the heritage-rich town center and ensuring the two-story addition does not surpass the current roof’s height. Vassens stone clads the exterior, sourced nearby, to resonate with the historical masonry.
What are some features of the nursery’s extension?
The extension connects two courtyards, providing a communal ground level with features like a northeast-oriented dormitory, distinct children’s toilet space, and a multipurpose room. It also includes three classrooms and a library, fostering architectural and ecological efficiency.
