On 29 October, at the Trafo in Baden, the Swiss Arc Award did something it had never done before. A four-person jury of Dominique Salathé, Ludovica Molo, Roger Boltshauser and Remo Derungs had worked through 188 submissions in several rounds down to a shortlist of 42, and gave the Bildung & Gesundheit category to Schule Wiesental in Baar. The public vote, the “Swiss Arc Award der Herzen”, went to the same school. As Baunetz reported on 5 November: “Erstmals wurde dabei ein Projekt doppelt ausgezeichnet.” The experts and the readers chose the same building.

The building is by PENZISBETTINI Architekten ETH/SIA, founded in 2017 by Daniel Penzis and Giulio Bettini at Alfred-Escher-Strasse 23 in Zürich. Their office page lists seven people today: the two founders, Isabel Ulbrich, Anna Jundt, Niclas Schlötke, Isotta Bizzozero and Alma Caspi, cand. Arch. ETH. Both founders were admitted to the BSA this year. In February 2019, about two years after they opened, Timbatec announced that the jury had ranked their project “Domino” first, for further development and execution. Seven names, a BKP 2 budget of CHF 56.9 million, 14,850 m² of floor area, and a school for about 560 pupils in 24 primary classes and four kindergartens. For a practice of that size, the scale itself is the story.

The grid is the method

The idea behind it is older than the office. In 1961 the Dutch architect John Habraken argued in De Dragers en de Mensen that a building should separate the long-lived “support” from the shorter-lived infill. Peter Cook’s Plug-in City later drew the same split as a megastructure, and it stayed on paper. Penzis brings a material-first habit from teaching the Materialwerkstatt elective with Prof. Annette Spiro at ETH Zürich. In Baar the split becomes simple: a regular 3.80 m timber frame. According to the project text on swiss-arc.ch, it works as a rack that non-load-bearing walls subdivide. Load-bearing and non-load-bearing parts are kept apart, so components with different lifespans can be swapped without touching the structure. Below ground is recycled concrete, above it timber. Photovoltaics and geothermal heat pumps bring it to Minergie-A-ECO.

The phasing is the part every school client in Switzerland will study. Haus Ost, with 24 classrooms in clusters of four and a triple gym, was built and occupied first. Only then were the old wings A, B and C demolished. The pupils never lost their school. Space for one more class stream is already set aside on the south façade of Haus West, so the next extension is in the plan before anyone asks for it. Ueli Berger’s yellow cube pyramid from the old campus was restored and reinstalled, and the stage-2 landscape tender lists a “Sitzpyramide”.

←TODAY: A Zürich office founded in 2017 delivers a CHF 56.9 m timber school on a 3.80 m grid and takes the first double Swiss Arc Award.
→3012: The frame outlives three generations of classrooms; only the infill changes, one bay at a time.
Fulcrum: A building can only be changed later if its frame and its infill were drawn as separate parts from the start.

A small office cannot carry a job like this alone, and this one did not try to. The swiss-arc.ch and ArchDaily credits name a long team, among them Ingenieurbüro Heierli and Timbatec on structure, Makiol Wiederkehr on timber construction and fire protection, and Schläpfer Carstensen on the landscape. The 2019 competition team was PENZISBETTINI with Daniel Schläpfer Landschaftsarchitekt, Heierli, eicher+pauli and Timbatec. The trade-off is real: a fixed grid saves every later decision only because it constrains every early one, and a room that wants 4.20 m has to argue with the rack. Offices like ours know the opposite failure better. The competition model that could be anything turns into an execution model where every wall carries load because nobody decided otherwise. The architects put the result plainly on ArchDaily: “The campus arrangement disentangles programmatic functions while preserving the communal idea of a school as a shared place.”

Atelier: For a studio of eight to twenty people, the lesson from Baar is that the structural decision has to happen in the first sketch, not in Ausführungsplanung. Once a team uses AI drafting aids, those tools copy whatever structure the template already holds, so the split has to be built into the template. Monday move: in your Archicad office template, add a fixed project grid and two layer combinations, “Tragwerk” and “Ausbau”, and make every new competition file start from it.

Hack: Check whether your exported model really separates structure from infill before the engineer has to ask. The open IfcOpenShell library, built by Thomas Krijnen, Dion Moult and many contributors, reads the standard LoadBearing flag on every wall. Any wall reported as None is a decision nobody made yet.

import ifcopenshell
from ifcopenshell.util.element import get_psets
m = ifcopenshell.open("competition_model.ifc")
for w in m.by_type("IfcWall"):
    print(w.Name, get_psets(w).get("Pset_WallCommon", {}).get("LoadBearing"))

The office describes its own work in one line: “wir suchen nach Interventionen, die den vorhandenen Charakter stärken.” Baar shows that line at the scale of a whole school, from a grid that stays in place to a pyramid that came back.

PAZ Takeaway: Decide what carries load in the first sketch, and keep that decision visible in the model: a fixed project grid, with load-bearing and non-load-bearing parts on separate layers from day one. Every later change then becomes a swap, not a redesign.

Open your last competition file, run the check above, and give every wall that comes back None its answer.