Biel Wood School (or, formally, the Department of Architecture, Wood and Civil Engineering (AHB), source of much of the timber energies in Switzerland at present, including Timbatec and its TS3.0 project, with the TS3.0 test pavilion in the upper left foreground – Photo AHB (All photos in this piece are credited Timbatec unless otherwise stated.)

Vorsprung durch Timbatec

Switzerland's twenty first century return of timber has been propelled by start-ups and spin offs, innovation and also, increasing numbers of trained engineers. Of the new young companies, Timbatec have been pushing the timber envelope, including developing the largest span timber panels to emerge so far.

Timber tech guru - Mr Zöllig in pre-work
day mode – Photo Timbatec

To get a sense of the changes in Swiss timber construction one only needs to digest a single statistic: since engineering was added to its curriculum in 1987 over a thousand timber engineering students have passed through the doors of the Biel wood school – or, to give it its technical name, the Department of Architecture, Wood and Civil Engineering (AHB), University of Berne or Fachhochschul – and for the most part the graduates have all become gainfully employed, working and researching across the sector.

One of the establishments students send their CVs to is Timbatec, itself a child of AHB, and one of two sizeable and increasingly influential timber engineering outfits; the other is Pirmin JungStefan Zöllig, AHB alumni, founded Timbatec in 1994 in Steffisberg, (near Thun) and the engineers have been growing ever since, opening a Zurich office in 2010, followed by Bern and, most recently, an outpost in the Austrian capital, Vienna. Today there are 40 engineers, with nearly all of the team ex-Biel school graduates. Pirmin Jung, the name of the founder as well as the engineering practice, likewise traces his engineering origins to Biel.  Each have become significant contributors to the growth of timber construction through their quarter-century+ lifetimes, having ridden and continuing to ride the wave of exponential growth. Timbatec, however, through Zöllig, are involved in several research and start up projects, giving them a broader profile than that of a straight-forward engineering company.

Through Timbatec’s first years, the company was focused on small housing projects and individual houses as there wasn’t enough of a market for engineered timber, using the timber structurally in frame buildings. In the late 1990s the scale began to increase, with the commissioning of the first timber multi-housing blocks. At the time there was, Zöllig says now, talk of four to eight storey timber towers: “I didn’t believe it, that there wouldn’t be such big structures.”

Timbatec's TS3.0 test pavilion at Biel, weighed down with stones – All photos and illustrations Timbatec unless stated otherwise

Although the engineers initially completed 150 part-wood, part-steel and concrete projects and then, beginning in 2009, another 300 entirely wood-framed buildings, Timbatec really began to come into its own in the years after its research arm was founded 12 years ago. As to Zöllig himself, he originally apprenticed and trained as a cabinet maker for four years, before the sideways move to the Biel school. He then worked in a timber engineering company, before beginning Timbatec in 1996. Asked what he does now, Zöllig describes himself as “mainly a developer, researcher, and product developer.” He doesn’t mention that he also is involved in leadership programmes, which includes Neuro-Linguistic Programming (NPL) training. As far as the timber research agenda is concerned, it has been primarily focused on TS3.0, the niftily acronymised name for Timber Structures 3.0, a reference to the new dimension claimed for their large-scale ceiling panels and slabs, advancing on solid timber (1.0) and CLT (2.0.)

The sort of scaling TS3.0 is bandying around is based on several years’ R&D on what’s delicately known as butt joint bonding, which Timbatec, along with its Biel alma mater, ETH-Zurich, and industrial partners Schilliger Holz, and Henkel & Cie, initiated in 2009, with the main research thesis completed in 2014. The research focused on bonding technologies, which introduced the possibility of producing multi-axial bearing boards – where the load a ceiling is carrying is shared across the whole panel - with point support or folded-plate structures in all shapes and sizes. While the promotional hook is rather too hyperbolic, with claims that the system can ‘create beams of any length and slabs of any size’, load-bearing flat wood ceilings extend to 8m x 8m with carrying loads of up to 5 kN/m². A significant part of the six year research effort engaged with adhesive bonding, gluing the butt joint edges, in collaboration with engineered timber’s principal polyurethane manufacturer, Henkel.

But what about the resin? In a time when a new front is opening up with adhesive-free engineered timber, is this really that revolutionary? Zöllig shrugs this off, saying it is such a comparatively small amount. For every 1000m tonnes one litre of the polyurethane cast resin is needed, he says. “Already, one thing which is really special is the edge treatment, normally with two pieces of wood, with glue you double the strength. If you give it the special pre-treatment - it is 20 times as strong.”

Widespan – Markus Handl distribution centre uses TS3.0 technology -  Right hand render ATP Arkitekten

Zurich-Unterstrass deeper green housing block by Wellmann
Architekten – Render Wellmann Architekten

The largest spans reached this far are on a project in, appropriately enough, Vorarlberg, one of Europe’s eco-construction capitals. At the new food production and distribution facility building of Austrian Tyrol company, Markus Handl AG, 650m2 comprising 3.5m wide slabs, has the joints glued together using the specially developed Henkel polyurethane glue. The architects, Innsbruck’s ATP architect-engineers have combined Zöllig and co’s TS3.0 system with another, this time Austrian technical R&D project, Rothoblaas’s, Spider column connectors. Together the two systems allow considerably more design flexibility within flat slab systems, opening up spaces by reducing supporting posts and potentially doing away entirely with beams.

The first building the TS3.0 tech was trialled on was in spring/summer of 2019. Since then early projects have included four family houses, and now a multi-housing project, where the basement groundworks are completely concrete free, replaced by CLT, edge-glued by the TS3.0 timber tech. Not dissimilarly the four storey, 15-apartment Fasenenhof block in Frankendorf, Baselland canton, demonstrates the TS3 system applied to medium-rise residential buildings. Compared to concrete, according to architects Scherer of Scherer Architekten, the carbon footprint was cut by 600 tonnes. In total, as of late 2020, fifteen projects have been completed, with eight in the pipeline.

Fribourg Hospital timber extension

One of the latest projects is a five-storey housing unit in Zurich-Unterstrass, with a deeper green agenda and aspirations. Wellmann Architekten’s housing block features clay panels, sheep wool insulation and flexible walls integrated with the TS3 timber slabs. It has pursued optimising its energy strategy to meet the Canton based GEAK-A energy standard, while at the social level the design aims to support communal and intergenerational living. Again, the CLT slabs were pre-primed at Schilliger’s factory before the jointing grouting was applied on site to the edge faces of the slabs, creating the extra-large dimensions and spans, with the forces carried over to points on the exterior walls and concrete stairwell.

How much of the revolution this actually is, is something of an open question, though also, arguably, a matter of take-up. Timbatec’s press person, Simon Meier, believes the sky is the limit: “the aim is to build whole cities – carbon free city and carbon sink city is what Zöllig promotes it as.” Similarly on the web the 'timber revolution’ is about whole TS3.0 "hospitals and even entire cities.” All this is to be expected from the PR department - Meier may have been getting a mite carried away, and Zöllig is slightly more measured when I point these excitable phrases out. But, he suggests, one can imagine the potential. And, if there aren’t complete cities quite yet, Zöllig points to how the systems could work well when dropping new floors and extensions onto buildings and notes that there is a just such an extension – a whole building inside a hospital – in the French-speaking town of Fribourg. “The more buildings we do, the longer we work, the more knowledge is needed, and is built up,” he continues. There is further development needed on the statistical analysis software, aspects of the quality assurance process need to improve, and the actual panels will likely advance. At present they are thick, thick panels, consuming large amounts of laminated timber. A current research PhD within ETH Zurich’s structural timber department is focused on lighter weight panels.

TS3 is but one of Timbatec’s research projects, though easily the most developed and realised. There are a suite of related materials extending the main TS3 tech. Research has also focused on elastically-bonded chippings, used in ceilings for its acoustic properties, as a replacement for hybrid concrete-timber hybrids. Stairwells have been another focus for reducing concrete dependency with a new 2019 housing block, Krokodil in Winterthur, integrating timber rather than concrete stairwells.

One main current piece of research is titled DeepWood. As with TS3, the Biel Wood School is the primary academic partner on this Building Information Modelling (BIM) related research, focused on developing an integrated system for a diverse number of partners to work as one on BIM across the platform, at an all-through level from planning through to delivery. Applying Catia programming, DeepWood is testing at a cross company level, the various stages of a build, using a test construction, a housing block in Timbatec’s home town, Thun, to document and record the results of the collaborative project, in effect the researchers’ Living Lab. The Thun project also features an entirely concrete free basement groundworks.

The concrete free ground floor under construction

If the excitement and innovation appears to be around the r&d, the principal Timbatec engineering operation also get to work on novel and precedent setting engineering projects for the main Timbatec engineering company. These include the first timber-roof for a road tunnel – which also acts as a safe 50 metre long wildlife overpass at Rynetal, Suhr on the N01 motorway.

Timber tunnel and animal crossing at Rynetal, Suhr

When asked, Zöllig describes the company he got up and running as “100% born in Biel.” He believes the wood school has not made the impact internationally it deserves, given its work and influence: “it’s under-communicated”, even though it is the only academic establishment in the country. Andrea Frangi, the lone Prof heading up ETH Zurich’s Structural Timber leads a team of twenty, compared to 200+ academics and post-graduates primarily focused on the 20th century material, concrete. Today hitting mid-life, he is part of an in-between generation, younger than the likes of Hermann Blumer see the Annular Unstructured profile here, Ernst Gehri, Julius Natterer and the forefathers of AHB in Biel, though also significantly older than the recent waves of graduates spilling out of the border town and helping provide the technical brain power to facilitate much of the ongoing timber boom.

Zöllig is complementary about Blumer’s work even if it sounds as if he thinks the Appenzell engineer has suffered from being a lone figure, too much ahead of his time; less so of Natterer: “No-one could use any of Natterer’s tech, especially the concrete-timber hybrids, they were not worked into products.” Now he sees many opportunities compared to the past – “a different time.” One is Scrimber: another approach to using wood compared to conventional glulam preparation which uses only 30% of the trees; with the Scrimber method 100% of the wood is used, says Frangi, before adding that there are four new start-ups, comparable to TS3.0, that he is working on.

We’ll see how much this will come to pass. Perhaps it is, as the publicity is attempting to hype it, the next generation of CLT. Perhaps it will be. There again, technological development around size and glue isn’t exactly a fundamental category shift.  Internationally, the PR material is very much focused on North America, and there are a small number of experimental showcase buildings already completed in Canada. Absolutely more locally, Timbatec have opened a new office in Delemont in the Swiss Jura. Close to heavily forested French north-east Alsace-Lorraine, where timber building has been growing over the last decade, the office was opened on the back of a major stadium project they are involved in building. What is clear is that within the confines of Switzerland, Zöllig and Timbatec are proof of the influence of Biel’s Wood School on the emerging story of twenty first century timber. With 1000+ timber engineers trained in the interim since Zöllig’s time, it stands to reason that there’ll be whole further waves. For now though, Timbatec can be considered a provocative fruit from Biel’s forest factory.