Roland Zumbühl Picswiss/CC BY SA 3.0

It was working on Kollegium Gärtnerei which convinced Stephan Küng, Küng Holzbau’s heir, to invite the small young studio to design a brand new factory work hall for his own new timber venture. “We were a young office, the same age, and from the same place, so he thought he’d give us a chance,” says Seiler over the phone nearly fifteen years later. Stephan’s father, Walter Küng founded the carpentry construction and joinery company in 1977. It grew steadily and by mid-2000 the company developed a timber building system which quickly proved popular. It brought the need for new facilities and, looking for an enthusiastic local studio, Küng Holzbau returned to SeilerLinhart Arkiteken.

What was unusual – indeed close to unique in Switzerland at the time – to Küng Holzbau’s system was that it was all-wood. The system, titled Holzpur (rough translation, ‘Pure Wood) entirely dowel-based system – neither glue nor metal is used –, and if needed wooden nails. High-     tech machinery is used to join the locally sourced material together into various forms. Success with their buildings and the arrival of new digital tools, not least CNC routers, made such a facility an obvious next step.

Before developing Holzpur, a glut of maturing beech wood from across central Switzerland, and specifically Obwalden, had become a problem for the regional forestry sector. Liable to movement, and therefore too unreliable as structural timber, beech hardwood had fallen on hard times, and through the 1980s and 90s, as a cheap, unpopular wood it had been relegated to ending up as parquet flooring across the country. Wanting to avoid this outcome for other species, Walter Küng and his colleagues began to think of new ways to use other local tree stands, primarily spruce and fir. Küng Holzbau developed a prefabricated solid wood construction system, which, using specially developed machinery and the arrival of CNC routing, could produce glue-free boards, held together by beech dowels.

The workshop facility was planned out by Seiler, Linhart and the younger Stephan Küng, who’d been working in the family firm since 2005. The workshop was to reflect both tradition and the future, the old and the new. The architects suggested that its main façade be covered in a layer of protective shingles. A rain screen material is old for sure, but given the building was so much larger than the domestic scale. So, why not use oversize shingles? If this referenced tradition, above the workshop’s roof, would be about the experiment. The finished building’s roof deck juts outward, semi-cantilevering over all four shingled walls. Thin timber slats point upwards to the roof’s oscillating ridgeline, the geometry of the slats makes each a one-off, and requires individual CNC milling. Here, in this expanded roof feature is the futuristic, computer-aided half of the work hall, and Küng’s message.

Küng Holzbau’s first SeilerLinhart designed work hall 

Outsize shingles on the work hall 

At seventy-eight metres long and thirty-eight meters wide, the end ribbon windows extend right across the building’s width. A skeleton frame holds up the workshop, much of the timber locally sourced.  Both walls,      including their load-bearing elements and ceiling, are made of solid fir and spruce, while large glulams have been used for the series of lattice girders punctuating the hall’s upper spaces. State-of-the-art machines were installed – all from, the website adds, Swiss manufacturers – for a production line, which runs the fifty-four meters length of the hall. The walls needed to work as hard as a sizeable five ton crane for lifting timber was also part of the brief, its rails running along the side of the hall, again on wood supports. Unusual at the time, what rather lessens the natural materials impact is the specification of rock wool for insulation,      given the direction the manufacturer would turn towards in the immediate next years.

The production line, including cutting and assembly, is largely automated      and consists of a three-machine section and twenty-six axes. Preparing the boards is an involved, though CNC-controlled and fully automated, process. First, multiple 3cm-thick spruce and fir boards are stacked crosswise. Large openings like windows and doors are already precut. Between the boards wool, cotton and rag fleece have been added to ensure air-tightness removing the need for vapour barriers before a diagonal layer braces the boards. Next, at the intersecting points of the layers, holes are drilled and beech dowels are pressed in under tension. Finally, the last part of the production line mills contours, cuts connecting grooves and openings for sockets and cables. Walls, ceilings and floors can be manufactured, including flooring laid without cement, all with high levels of rigidity. The Holzpur comes with Swiss certificates, including ISO certification, the Swiss Minergie, Minergie-P, and Minergie-Eco standards.

In current-day industrial forestry, arguably the closest one comes to this romantic strand of forest lore are practices which work with the lunar calendar, cutting and felling trees through the winter months of the seasonal cycle. This is usually the immediate weeks before Christmas before the new moon, when water sap is at its lowest in the wood, resulting in minimal shrinkage, less risk of infestation and stronger, healthier tree trunks. Trees that are growing higher up the valley ridges, closer to the tree line and the mountains, are also said to ensure higher quality wood. A shorthand title for these forestry practices is ‘Moon Wood’.

By the time the Holzpur system was up and running the younger Küng was immersed in ‘Moon Wood’, and he decided      to commit Küng Holzbau to using ‘Moon Wood’ as the source of most of the wood. Obwalden wasn’t exactly short of steep forested uplands, and      the network Küng had developed was strictly regional. Just as stands were harvested by local foresters, transport was organised among regional transport companies, and processed in nearby mills across the Central Switzerland region before returning to Küng’s Alpnach workhall, helping reduce the embodied carbon to about half the timber industry average.

Moon Wood rising 

Stephan Küng and colleagues checking recently harvested logs – photo Küng Holzbau

Moon Wood is hardly a new idea, because it has been used by foresters for centuries. In recent times, the Austrian company, Holz100, were the first to re-introduce the ‘pure’ all-wood philosophy and practice into their work. Founded by Austrian forester Erwin Thoma, a forestry economist who, inspired after      researching his carpenter grandfather, uncovered a trove of pre-modern wood knowledge, which he began to promote through books, before setting up Holz100. Moon Wood’s cosmological basis is comparable to natural medicine, traceable to Renaissance practitioners such as Paracelsus and Hildegaard of Bingen. Unsurprisingly, its claims have brought academic critiques and refutations, though these don’t appear to have deterred Erwin. With well over one-thousand all-wood buildings under their belt, before Holz100 splintered into different companies, its rump today operates under the commercial aegis of Thoma Holz out of Goldegg, south of Salzburg. This is also the home of Erwin, while former partners set up NurHolz in Germany’s Black Forest. What there wasn’t with any profile, however, was a Swiss manufacturer of glue-free all-wood timber. By expanding into Moon Wood, Stephan Küng stepped into these absent shoes.

The first project of their own that Küng Holzbau decided to introduce Moon Wood to was Stephan Küng’s own family home. With the workhall such a success, Küng once again turned to SeilerLinhart. 

An update on traditional Obwalden timber houses, sitting on a raised plinth with a gabled roof and showing off a sprinkling of decorative features, Haus Kdemonstrates both Küng and SeilerLinhart’s domestic side of building, along with a rather non-modern attachment to the past. Topped with a pitched roof with deep overhangs, the family home liberally deploys a variety of hard and softwoods, including Moon Wood in its solid wood structural frame. It is comprised of untreated spruce and white pine, while also introducing other natural materials, including rammed earth, tadelakt plaster and bamboo into the material mix, all done by Küng and colleagues.

The next project: Stephen Küng’s home 

The Moroccan tadelakt plastering technique is used on the bathroom walls, while a stove has been built into the rammed earth core – taken from the foundations – helping to heat the entire home. Inside, a mere six-meter-squared of firewood is needed through all the winter months, reducing what promotional material calls ‘electrosmog.’ Wood is predominant, a single layer of silver fir boards lines both interior and exterior surfaces providing a source of winter warmth, with fine carpentry woodwork and joinery detailing are a feature throughout. Doors and windows are made from another, lesser-known Swiss hardwood: chestnut, and oak is also used where the floors and walls meet. Metal connectors have only been applied to join the Moon Wood panels to the façade, internal walls and roof, otherwise it is an all-wood, all-natural materials home.

Peter Zumthor’s workshop – Photo Lucas Pavlina

By the time Haus K was completed in 2016, months before the younger Küng took over the firm, both Küng Holzbau and SeilerLinhart were already looking ahead to their next collaboration. Küng’s profile and the company had grown through the last years, their work respected, as was the care and commitment to the all-wood, and indeed Moon Wood, agenda. One sign of this was Switzerland’s cult anti-starchitect, where Peter Zumthor asked the carpentry company to build his new workshop studio in Haldenstein, Graubünden.Further – See FDR8’s in-depth Peter Zumthorfeature.

If flattery from famous architects has been one form of attention, neither SeilerLinhart nor Küng Holzbau were likely prepared for the tsunami of media coverage and viral spill rippling out across the internet in the aftermath of completing the office HQ building. Indeed, they were still a small Central Swiss wood company. Set a few yards across from the work hall in Alpnach the Linhart-     designed office building is a simple, resolved and strikingly elegant composition. Four storeys tall, and built around a concrete core, this compromise with Swiss fire regulations only somewhat detracts from the crafted delicacy of the building. Each above ground level floor features balconies ringing all four equal-sized faces of the building. Pairs of vertical slats push upwards from each floor clamped to horizontal beams jut out of the balcony undersides. They join the fourth floor’s roof’s outstretched overhang, a protection from solar glare and weather, removing the need for solar for blinds. As an ensemble, the rhythm of the double slats brings an element of the threaded and woven to this poetic gesture.

The Moon Wood carvings – photo Oliver Lowenstein

Küng Holzbau Alpnach Headquarters 

However, the attention was of a completely different order than with the work hall. When I visited back in 2022 Linhart was entirely friendly, but three years later on the phone he acknowledged that he’s worn out by the popularity, and “telling the same story over again and again.” This said, it has served as a particularly effective poster child for solid all-wood construction, Küng Holzbau’s Moon Wood message reaching parts other ways couldn’t, while drawing the world to SeilerLinhart and its small patch of central Switzerland. What is also evident is how rather than there being a single hi-tech/hands-on tradition and tech language, there are any number of different dialects, each trying to calibrate the relation in their specific way.

When I visited over the summer three years ago, a fourth building, the second large workshop was also operational. Heavy with timbers waiting to be used, the new workshop again played with the old and new motifs. Hard by the office HQ it also repeated variations on the design themes, the extended roof and slats, the slender row of timber rods along the sidewall façade, and ribbon windows at its front. Once again there were photovoltaics attached to the roof, likewise, feeding the energy requirements. But this time, the building wasn’t by the architects. Instead, Team AG, another small Sarnen studio have flattered SeilerLinhart, their design bearing many of the hallmarks of the first project.

The next workshop – photo Martin Kach

Inside the new machinery was humming, including a TechnoWood TW-Mill machine. Taken together, the impression was of growth and dynamism, not perhaps entirely surprising given the Holzpur system comprises eighty percen of their workload.

The growth included working on a solid wood furniture series, and a floor heating system made from wood, titled Lignotherm. Trialled on Haus K, where the underfloor heating loops were embedded into milled beech panels, rather than attached to metal or plastic clips, the system has since been commercialised. Küng boasts that this is the first all-wood system available, with the heating pipes held in place by spruce battens sitting tightly within the beech underfloor panels. There is neither concrete, metal or plastic in the system, an added potential benefit is that it is dismantlable. 

The timber builders are also eyeing up a larger scale as well, with five-storey buildings – the limit with Holzpur – on the way. There are already the first solid wood apartments in Alpnach.

One of SeilerLinhartest projects, new housing appearing on Küng’s Facebook page illustrates again the studio developing its established design language. Part vernacular, part modern, as architectural and woodworking aesthetic, what’s happening here recalls Graubünden’s regional architectural culture (Further – FDR8 for Graubünden’s regional scene), which Linhart acknowledges as an influence early on. Here, the pair have made an Obwalden regionalism of their own.

It isn’t only individual houses either. In the lakeside village of Sachseln on Lake Sarnen (or Sarnensee) the architects have taken on the very different dynamics of urban densification and place-making in a small village rather than a city or sizable town. Acknowledging how many people continue to live in villages across Switzerland, and how, as elsewhere, villages need to maintain and increase the level of available homes, the architects developed a seven-point manifesto for this gentle densification project. Into a modest plot of land, Linhart sought to drop three dwellings, and to renovate and rebuild a fourth, which had a preservation order restricting demolition. For Linhart Spalihof“is a small piece of urban planning, which created clear outdoor public spaces” with the aim of village scale gentle densification. The three new-build homes take the Swiss vernacular chalets as their starting point, once again conveying their signature combination of old with new. Dressed in a subtly contrasting patina of dark olive greens, the two four and one five-storey housing blocks contain column grids which allow for floor plans of about eighty-seven-metres squared and between two-and-a-half to four-and-a-half rooms in each.

Spalihof – with the original renovated Spalihof right

The structural timber system has been left exposed throughout, with posts quartering out rooms. Externally, verandas add to each apartment’s space, while at ground level the landscaping by Luzern’s Freiraumarchitektur of the hilly terrain provides quietly convivial spaces, both to spend time in and to traverse. Close to the boundary edge, a miniature wild meadow has been planted, along with flowerbeds at its heart like a central square. The incline also permits garages at ground, rather than underground level, removing some of the usual excessive amounts of concrete, a small-time carbon gain. The fourth building, the eponymous Spalihof, is a renovation project, with the architects drawing out its vernacular charm by reshingling the façade and contrasting light with dark timbers inside what was thought to be the village’s oldest building.

Spalihof wasn’t a partnership with Küng Holzbau, but another of their most recent projects is. This is a new Headquarters for the regional Obwalden Cantonal Bank (OKB) built in a business park on the edge of Seiler’s home town, Sarnen. The five-storey building is also SeilerLinhart’s first non-residential timber project. There are similar moves to the Küng HQ office, including a Holzpur timber skeleton surrounding a concrete core. Inside, rather nakedly exposed spruce and ash columns and crossbeams rise across the publically accessible two-storey entrance hall, while another Küng office motif decorative features on the dark wood posts also punctuating the façade, and are complemented by patterned carvings – presumably CNC’d rather than handmade – above each window. The ground and first floors also feature aluminium shutters in a complementary lighter brown hue. Looking at the building via the limited lens of the internet, the intensely orthogonal block marries meticulous Miesian strictness, with something almost criminally indulgent when it comes to ornament.

Photographs of the Obwalden Bank building are a reminder of just how architectural, but also how Swiss SeilerLinhart are. Indeed, their body of work is hardly confined to timber; there is a long list of non-timber projects to scroll through on their projects page. But the extent of their embrace of wood remains marked, specifically their benefactor’s Holzpur and Moon Wood. Already outside the gilded triangle of the Schweizer-Deutsch Basel-Zurich-Bern architecture but having learnt from its world while students (Linhart was also an assistant at ETH Zurich, though to Vorarlberg’s fiery Dietmar Eberle when the latter was dean of the architecture school) the pair have cultivated an architectural aesthetic applied to the part of Switzerland they’ve grounded themselves in, and the material palette they work with. When it comes to their wood works there is the formality and seriousness of the high profile, internationally recognisable Swiss mainstream. Partly because of their one-time mentors BearthDeplazes, but also because their work has occurred entirely outside its geographical placement, and with materials at the far end of mainstream acceptability. But also folded into this is a clear absorption in the regional vernacular, the decorative and the embodied, which is reminiscent of other Alpine regional scenes, though with its own accent. All this sliced through with the challenges Küng Holzbau has brought to the table, both technological and ideological. A particular combination, in a particular region at a particular time.