Fiechter Salzmann Extends Werner Künzi's Listed Mösli School in Ostermundigen with Concrete, Spruce and Red Steel

Adding to a listed school is a test of restraint, and most architects fail it in one of two ways: they either imitate the original too politely or stage a contrast loud enough to drown it out. At the Mösli School in Ostermundigen, on the northern edge of this suburban municipality beside Bern, Zurich-based Fiechter Salzmann took a third route. Their 1,500 m² extension, completed in 2024, lengthens Werner Künzi's long school wing to the west and houses two kindergartens and a day school, all without asking you to notice where old stops and new begins.

What makes the project worth your attention is not the gesture, because there barely is one. It is the way the team read Künzi's orthogonal system of piers, cornices and flat roofs as a set of rules rather than a style to quote. The complex is a cantonal K-object, protected as worth preserving, and the brief rewarded a scheme that extended it in a way the jury called natural and economical. We think that phrase undersells it. Behind the deadpan exterior sits an interior full of exposed timber, red steel and saturated colour that turns a heritage obligation into a genuinely joyful place for small children.

A Frame That Continues the Grid

From the lawn, the extension reads as a two-storey concrete frame infilled with timber windows, the same grammar of strong horizontals and vertical piers that the heritage inventory identifies in the original buildings. The precast columns carry a crisp, almost industrial precision, and the timber-framed glazing between them softens that edge at the scale a child actually encounters.

Look at the corner, though, and you see the architects allowing themselves small inventions. A projecting bracket and horizontal louvres articulate the junction, giving the facade a shadow depth that Künzi's plastered surfaces suggest without spelling out. It is continuity achieved through proportion and rhythm, not through copying details.

Corridors as Streets, Stairs as Events

Inside, the restraint gives way. Corridors run beneath exposed timber beams, with red floors, red-framed glass doors and pendant tube lights that set up a steady, playful cadence. Daylight enters from the side, and a glass block wall filters views of the trees without letting them become a distraction.

The concrete staircase with its red steel balustrade is where structure and colour meet most clearly. The timber ceiling overhead, the raw concrete flights and the painted steel each keep their own identity, and that legibility matters in a school. Children learn how a building is put together simply by walking through it.

Rooms Scaled to Small Bodies

The classrooms are open, column-punctuated spaces organised around freestanding cream cabinet blocks, which double as storage and as soft dividers. A timber column holds the centre while glazed doors and a tree outside keep the room porous. It is a flexible plan, but not a featureless one.

The washbasin alcove is a small masterclass. Three taps at child height sit on a green speckled top, framed by board-marked concrete and lit by a round wall light. Fittings like this are usually specified from a catalogue and forgotten; here they are treated as architecture, and they carry the colour logic of the whole interior.

Regional Spruce in the Joinery

The entrance cloakroom shows where the project's material ethic is most tangible. The joiner used some 16 m³ of spruce sourced only from the surrounding region, for door frames and leaves, handle strips and the three-layer solid spruce back panels of the lockers. Colour-lacquered sides, red dividers and oiled oak seats complete an assembly that is both durable and visibly local.

The kitchenette repeats the palette: green counter, glass block window, red-framed timber door over a red floor. The extension has reportedly been recognised with a Best Architects 2026 award for its sustainability, and moments like these explain why. Sustainability here is not a technical add-on; it is the honest choice of nearby timber, worked carefully and left to show.

Plans and Drawings

The drawings make the strategy plain. Künzi's complex consists of four cube-shaped pavilions around a square courtyard, linked by covered walkways to an elongated wing containing the gym and a caretaker's flat. The new volume simply carries that long wing further west, sitting at the edge of the listed ensemble and leaving the courtyard composition untouched. The upper-floor plan shows central stair cores and thick walls organising the classroom and common spaces, while the 1:40 section reveals roof skylights that bring light deep into the plan.

Notably, the competition-winning scheme stayed close to a 2019 preliminary design by Suter+Partner Architekten of Bern. Rather than treating that as a constraint, Fiechter Salzmann used it as settled ground and put their energy into section, material and detail. The wider works also included a new all-weather court with two outdoor equipment rooms, a refurbished flat roof on the special-purpose wing and landscape design by Andreas Geser.

Why This Project Matters

Many Swiss municipalities face the same pressure Ostermundigen did: growing populations, a school space plan demanding more kindergarten places, and a protected postwar complex that cannot simply be replaced. The Mösli extension offers a convincing model. It accepts the heritage frame completely on the outside, then uses the interior to deliver the warmth, colour and tactility that young children need.

For architects, the lesson is that respect for an existing building is a matter of reading its rules, not reproducing its surfaces. For clients, it is proof that a modest public budget and a disciplined brief can still produce rooms with real character. We would happily send our own children down those red corridors.

Mösli School Ostermundigen by Fiechter Salzmann. Location: Ostermundigen, Switzerland. Area: 1,500 m². Year: 2024. Photography: Andreas Buschmann.

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