Burkhalter – Sumi – Timber construction: facade/roof



What is the reason for these architects’ intense preoccupation with wood? Christian Sumi’s father was a cabinet maker. Did childhood experiences then lend him a special relationship to this material, just as Adolf Loos has a special relationship to stone? Such a question gains more than mere private meaning only when it is transformed in the architects’ thoughts into a technical issue. In using the word technical, I refer to the German poet Bert Brecht who wrote that works are made and that we, while reading a book for example, should read it “as technicians”. Thus we should ask ourselves, “How are Burkhalter and Sumi’s works made?“

[…] In the publications of their works. Burkhalter and Sumi like to show dense series of sections. These describe the places of a building where the relationship between the parts is realized as thinking which varies a construction according to the specific conditions of these places. On the one hand, these sections are technical directions for building. On the other hand, they thus define the thinking in which these directions have their common base: as a thinking that moves in that these drawings resemble photographs by Eadweard Muybridge of persons making certain movements.
The series of sections seem to crowd the space. It would be wrong, however, to assume that the architects were merely interested in the envelope and not in the spaces that it encloses. The skin is important to them for several reasons ranging from technical and economic considerations to those related to the perception of a building as a strong form or as a form which is whole.
Thermal conditions make it difficult to reveal the load-bearing or “real” construction hidden beneath an envelope that, at most as a sign, refers to it. Thus, when nailed down, “truth of construction” changes camp out of necessity: now it refers to the protective construction. This realization explains the intensified confrontation of German Swiss architecture with the envelope. The necessity of insulation against rain, wind, and cold, for example, rather than being a technical issue, becomes one of design leading to new images. Construction remains, in Adolf Loos’s sense the “reason for form”. Now, however, it concerns the construction of the skin.

Literatur: Martin Steinmann, Sensuality and Sense – the architecture Marianne and Christian Sumi in: a+u 308, may 1996 page 46 ff.

Haus Pircher

This building rests atop an existing garage situated on the slope of a vineyard. Its two forms follow the garage’s stepped structure with each one built using a different construction system: one, a conventional post-and-beam construction; the other, a non-load bearing frame. The cross-section shows the rafter roofing, supported by the metal T-beam with round steel supports and the sandwich construction behind – a solution typical of Arne Jakobsen in the 1950’s.

Haus Brunner

Again, the building volume is divided into two adjacent, shifted elements. Bedrooms are in the section on the slope, while the space to the south holds the residential wing and atelier. As with the Pircher building, we’ve faithfully adhered to modern 1930’s Swiss timber construction traditions (Paul Artaria, Emil Rot, Hans Fischli) whose detailing we’ve almost archeologically unearthed and emulated; modernistic compact volumes and windows aligned flush to the facade are juxtaposed with classic rafter roofing. The section illustrating the rear-ventilated atelier facade shows wide, cantilevered rafters. Rafters and roof elements are so strictly divided that one seems superimposed on the other. Multiple narrow rafters exaggerate this effect.

Forstwerkhof Turbenthal

This modular system for four forestry facilities with three parts each (hallway, garage and locker room) can be assembled in different configurations according to location. This project signals a paradigm shift. The traditional rafter roof of the previous buildings has been replaced by a box-beam construction with integrated insulation. Abandoning the cantilevered rafter roof wholly eradicates classic facade-roof relationships and rejects this characteristic of timber constructions. Here, only the fine shadow of a 3-ply panel indicates the presence of a roof. The support structure’s outer planking has been replaced with weightless wind paper, an ecological advantage. The framework consists of exposed, rough-sawn planks.

Kindergarten Lustenau

This project refers explicitly to Max Bill’s proposal for the Swiss Pavilion at the 1951 Venice Biennale. Two diagonally-positioned volumes (one for a Kindergarten and one for an infant station with care facilities) separate two other zones; a single-story gym and an outdoor playground. The facade’s playful, seemingly arbitrary vertical and horizontal windows overlooking the playground call to mind a child‘s toy box while contradicting classic timber construction expectations as well. The facade consists of a ventilated, front-and-back-planked frame construction; the roof structure is of heavy 16 cm thick laminated wood panel (BSP) with insulation.

Kaufmännische Schule Laufenburg

The school‘s defining architectural characteristic is the entrance hall‘s sloping, elongated roof. Its compressed, wedge-shaped entrance (a sort-of lateral entryway) makes the one-and-a-half story hall appear bigger than it actually is. The solid construction has a rear-ventilated wood facade acting as a catch-all-balls backdrop for the playground it faces, and has a rafter roof analogous to the Pilcher and Brunner buildings‘. These rafters however are cropped and define size and rhythm of the facade panels.


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