In 1875, Leonhard Lehmann I moved to Erlenhof together with his pregnant wife and their one-year-old daughter Carolina, laying the foundations for what we know today as Blumer Lehmann.

At the Erlenmühle mill, Leonhard Lehmann was captivated by hydropower – and by the eldest daughter of his employer and stepmother. He married Carolina Ledergerber in 1873. He and his young family moved to nearby Erlenhof – presumably initially as tenants. This is also where the future heir, Leonhard II, was born in 1875.

In 1876, Leonhard Lehmann I bought Erlenhof, then also known as Eierli, for CHF 25,000. He also purchased the lower portion of Weierwiese meadow from his brother-in-law, Johann Martin Ledergerber Jr., along with the right to use water from the Loobach waterway to operate a sawmill. It proved to be an astute decision, as construction was taking place all over eastern Switzerland. The area was booming.

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‘He then worked out that, if he immediately recaptured the water as it flowed from the mill back into the stream and channelled it into a pond, then built a sawmill further downstream, he’d get a drop of around eight metres.’ Leonhard Lehmann III, in his memoirs

In 1904, Leonhard Lehmann I’s firstborn son, Leonhard Lehmann II, (1875–1961) married Martina Eilinger (1877–1962) from Waldkirch. Their union brought the Lehmann and Eilinger families even closer together. Whether it was true love or not, one thing was certain: these family ties made good business sense. The Lehmanns owned a thriving sawmill operation, while the Eilingers had a successful carpentry business.

On his marriage, Leonhard Lehmann II took over the northwestern portion of Erlenhof that housed the sawmill. His father had taught him from an early age how to saw using the single-frame saw, cutting round timber into beams, boards and slats.

Besides the sawmill, the newlyweds had Mr Eilinger, Leonhard Lehmann II’s father-in-law and a master carpenter, build them a home. It was the oldest building at Erlenhof, surviving until very recently. Leonhard’s wife, Martina, also worked in the business, keeping the books. The Lehmanns’ progress is evidenced by employment contracts for external sawyers and domestic staff at the start of the 20^th century. The period of growth came to an abrupt end with the outbreak of the First World War. The sawmill ground to a halt, while the log inspection site was converted into a potato field.

‘Father and Mother had always entertained the idea of combining a carpentry workshop with the existing sawmill, so that the sawn timber products from the sawmill could be processed in-house and finished as construction timber,’ wrote Leonhard Lehmann III (1905–1995) in his memoirs. ‘That’s why my parents believed the best solution was to have me trained as a carpenter and, in 1922, I began my apprenticeship with Otto Eilinger in Niederhelfenschwil.’

Otto Eilinger? If that name sounds familiar, it’s because it is! Otto was Leonhard’s uncle from the Eilinger carpentry dynasty. So Leonhard III became the first Lehmann to combine the expertise of both the Lehmann and the Eilinger family: sawing and carpentry.

In 1927, Leonhard III returned from military recruit training and knew what needed to be done. Together with his brother Viktor, he established a carpentry workshop at Erlenhof. The carpentry workshop flourished, ‘business expanded rapidly, and outside carpenters joined the family workforce,’* wrote Walter Lehmann, Leonhard and Viktor’s younger brother. The carpentry workshop also allowed Erlenhof to tap into a new market. In the past, it was wainwrights, carpentry workshops and joiners who sourced timber from Erlenhof, but now the customer base included building owners, planners and architects. This was a crucial step in Erlenhof’s development towards becoming a timber construction company.

Like his grandfather, Leonhard III found his life partner at the nearby Erlenmühle. The couple married on 11 February 1935 and moved into the new building at Erlenhof. Nine months later, on 20 November 1935, the next heir (Leonhard IV) was born.

‘Baby boy is born,’ commented proud mother Martha, making a short and sweet note in her diary.
As was customary with the Lehmanns, operation of the sawmill and carpentry workshop passed to Leonhard Lehmann III, the firstborn, on his marriage. Brother Viktor was paid out and opened his own sawmill and carpentry workshop in Buttikon, Canton of Schwyz, which is still run as a family-run business to the present day.

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‘In 1934, we built a new house next to the sawmill. The only thing that was missing was a young woman and mistress of the house. But why search far and wide when good fortune lies so near? I called on Martha Ledergerber at the Erlenmühle. We got engaged on the third Sunday in September (the Federal Day of Thanksgiving, Repentance and Prayer) 1934,’ wrote Leonhard Lehmann III in his memoirs.

When Nazi Germany started the Second World War by invading Poland on 1 September 1939, the Swiss Federal Council ordered general mobilisation.

‘A nation of four million people stands guard at the country’s borders, composedly and resolutely awaiting the trials of these dark, bloody, murderous times,’ wrote the Neue Zürcher Zeitung. While somewhat exaggerated, 220,000 soldiers nevertheless entered active service, including Leonhard Lehmann III and almost the entire Erlenhof workforce.

During the war years, Martha Lehmann kept the business ticking over with the help of a farmhand and occasionally employees who were discharged from service. Due to petrol rationing, the Hürlimann tractor for the most part sat unused in the barn.

On 31 March 1941, Martha Lehmann wrote a letter petitioning the vehicle licensing authority in St. Gallen. ‘I still have 200 m³ of timber lying in the meadows that I cannot transport without the aid of petrol.’

The bells ringing throughout Switzerland on 8 May 1945 to celebrate peace probably weren’t heard in places as remote as Erlenhof. But the relief – and optimism! – that everyone felt was no doubt tremendous. In autumn 1945, the old sawmill, which had already reached the limits of its capacity before the war, was demolished and

replaced by an impressive new building (pictured on the right behind the log inspection site). The carpentry workshop was set up on the first floor. Pictured on the left: the farm run by Philipp Lehmann, Leonhard Lehmann III’s brother. In the middle: the home that Leonhard Lehmann II built in 1935, which housed the cafeteria until very recently. Behind it: the old factory assembly hall.

Otto Ledergerber, the brother of Martha Lehmann-Ledergerber, was employed at Erlenhof in February 1945. In his role as bookkeeper and office manager, the trained teacher and businessman maintained stringent standards of economy and discipline over the decades that followed. Apprentices were often told to straighten nails or sharpen pencils until only a stub remained.

The Willys Jeep was Leonhard Lehmann IV’s pride and joy. At 15 years old, he was allowed to go along with others to the military auction in Basel, where the legendary off-road vehicle was purchased. But that wasn’t all.

He was even permitted to (illegally) drive it back to Erlenhof all by himself. Here is a picture that he probably proudly took of the Jeep and his siblings – with Ruedi at the wheel, Markus on Ruedi’s lap and Norbert in the background.

On 27 October 1955, Oberberg Castle, the oldest building in Gossau, was engulfed in flames. The three-year reconstruction process got underway thanks to a fundraising campaign and support from local businesses.

It was an honour for the ‘timber men’ from Erlenhof to take on the carpentry work. Oak half-timbered walls, staircases, the ceilings in the Great Hall and adjoining rooms, the chapel ceiling and ridge turrets were all Lehmann productions.

As part of succession planning, in 1959 Leonhard and Martha Lehmann converted their family-run business into a public limited company: Leonhard Lehmann AG. This meant the company shares could be distributed and sold among the heirs.

One year later, Leonhard IV and his brother Ruedi Lehmann (the two eldest of Leonhard and Martha Lehmann’s seven children) took over the family-run business in the fourth generation. Erlenhof had 18 staff at that time – all of them ‘all-rounders’, as Leonhard Lehmann IV called them in a speech during the 100th anniversary celebrations in 1975. They set and erected timber, worked it in the sawmill and made furniture in winter.

The first bold move that Leonhard and Ruedi Lehmann, the new leaders at Erlenhof, made was to take over a timber construction business based in Edliswil and to relocate the joinery operations there too.

This not only allowed Leonhard Lehmann AG to increase its capacities. It also meant it could take on more production steps itself. In Edliswil, the company opened its very own window factory where craftsmen also produced double-glazed windows by hand.

The growing prosperity of the post-war period was visibly manifested in the motorisation of society. Between 1950 and 1970, the number of cars in Switzerland rose from 150,000 to over 1 million.

To manage all these vehicles flooding the roads, 1963 saw the start of Switzerland’s largest infrastructure project to date: motorway construction. In eastern Switzerland, planning of the A1 motorway led to extensive land consolidation, relocation and land improvements. This increased demand for new agricultural buildings like barns and stables – which was an opportunity for Leonhard Lehmann AG.

Leonhard Lehmann III had already specialised in barn construction. His buildings could be recognised throughout the region by their hipped gables. Now his sons started the ‘industrialisation’ of agricultural construction, presenting the Swiss T 110 standardised barn in 1962.

The special feature was that components such as the laminated wooden beams were prefabricated in series – a preliminary form of prefabricated construction, which Blumer Lehmann would later become known for. 1963 saw the company open its first planning office. Over the following 25 years, Leonhard Lehmann AG would build over 800 standardised barns (either by itself or with partner companies).

In the mid-1960s, Leonhard and Ruedi Lehmann had their business analysed by a German consulting engineer. The main criticism was insufficient mechanisation.

‘The labour costs for round timber handling are far too high.’* The sawing hall was also ‘completely lacking any form of transport mechanisation’. Overall, 80% of wages were being spent on transport work. In the years that followed, significant investments were made at Erlenhof – including in the likes of a cross-cutting and sorting system for the log inspection site that could be operated by a single worker.
* Investigative report for business consulting by G. Menzel, a qualified engineer from Lindau, dated 28 September 1965
 
 

Otto Ledergerber, the brother of Martha Lehmann-Ledergerber, had been the unofficial Head of Finance at Erlenhof since 1945. His son Magnus joined him in 1966, initially training as a carpenter before taking a seat directly opposite his father in the office.

Magnus Ledergerber’s talent lay in the meticulousness with which he navigated the complexities of government regulations and standardisation in agricultural construction. With this and his organisational skills, he made a decisive contribution to the success of Lehmann’s standardised barns. He ultimately outlasted his father in the business by 32 years before retiring himself in 2019.

In the midst of the 1970s energy crisis – the post-war era’s first economic crisis – Leonhard Lehmann AG celebrated its 100^th anniversary. The company had now grown to 80 employees, many of whom had been loyal to the family-run business for decades.

Erlenhof was a microcosm where the Lehmanns, the Ledergerbers and their employees all merged into one big family, eating and drinking together, celebrating and grieving together, laughing together and, above all else, working hard together too.

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‘I grew up in the business with some of you. You taught me how to saw and plane. You were my role models… You often secretly let me get up and close to machines and vehicles when Father wasn’t looking.’ And: ‘In many cases – and these were the most valuable experiences to me – I reconsidered and changed my opinion because of your ideas and critiques.’ Leonhard Lehmann IV, who was born at Erlenhof in 1935, speaking to his employees during the company’s anniversary celebrations.

On 23 February 1985, the Henessenmühle, first documented in the 15^th century, burned down to its foundations – only to rise back up from the ashes to its former glory a mere ten months later.

The Henessenmühle, first documented in the 15^th century, was also a popular destination for the Lehmanns. On 23 February 1985, it burned down to its foundations – only to rise back up from the ashes to its former glory a mere ten months later. The canton’s heritage preservation officer expressed his delight in his speech at the opening ceremony: ‘It is fortunate that there are still craftsmen who are familiar with the traditional techniques and who know how to work with the old materials.’ Where were these craftsmen found? At nearby Erlenhof, of course – and they included Leonhard Lehmann IV, who took charge of site management. But that wasn’t all. The following summer, even the mill wheel was running again – as a historical reconstruction.

In 1984, construction work began in Abtwil, in the Canton of St. Gallen, on what would become Switzerland’s most spectacular timber construction project of that time: the Säntispark leisure and shopping centre.

With a surface area spanning 13,000 m², it would become Switzerland’s largest timber roof construction, yet the challenge lay not only in its size but also in its design.

Waves below and an undulating roof above were on the architectural agenda. The construction engineers and timber builders who could implement this vision were Holzbauingenieure Steiner, Jucker + Blumer, Hermann Blumer and Leonhard Lehmann AG, which took the lead in the ‘Säntispark Timber Construction’ consortium. Together with the engineers, it also solved the complex construction-related and structural challenges, such as the 3D, curved grid – ‘a timber construction first’.

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‘The architectural highlight (…) is probably the gently sloping shapes of the roof, which span the pool landscape like an ocean of waves in an impressive, bold timber construction,’ wrote trade journal Lignum.

The mid-1980s, however, saw differences arise in company management, leading to brothers Leonhard and Ruedi mutually agreeing to split their business operations.

Leonhard continued to run Leonhard Lehmann AG under the new name ‘Lehmann Gossau’, with the enterprise including the sawmill, the timber trade, the timber market on Bischofszellerstrasse and, above all else, the timber construction operations, while his brother transferred the ‘newer’ architecture, window construction and joinery divisions to the newly founded Lehmann Arnegg AG.

Over a century after the water-powered sawmill was set up, computer technology began its triumphant procession – even at Erlenhof, where craftsmanship was king.

Erlenhof’s history has always been intertwined with technology. Over a century after the water-powered sawmill was set up, computer technology began its triumphant procession – even at Erlenhof, where craftsmanship was king. In the early 1980s, Hans Hundegger began developing a computer-controlled assembly system in Bavaria’s Unterallgäu region – with the support of potential customers like Leonhard Lehmann IV. So it came as no surprise that, in 1988, one of Switzerland’s first automatic assembly systems was delivered to Erlenhof: the legendary Hundegger P8, which enabled computer-controlled, automated and maximum-precision production of timber frame components.

Four years later, thanks to new and also computer-controlled timber processing equipment, the sawmill at Erlenhof could even process small-diameter timber such as native spruce. The investment was a commitment by Lehmann Gossau to native timber, which was coming under increasing pressure from foreign competition.
 

Beniwood AG settled on the southern grounds of Erlenhof. Beni Gmünder, the company’s founder, came up with the idea of processing the bark from his mobile bark removal machine and the sawmill into briquettes. The settlement of Beniwood AG brought Erlenhof a step closer to a closed timber life cycle: from sawing and timber construction to bark utilisation.

Erlenhof increased its focus on timber even further. In 1995, Beniwood AG settled on the southern grounds of Erlenhof. When the company was founded in 1985, it consisted of just a mobile bark removal unit, which Beni Gmünder, the company’s founder, used to debark tree trunks in forests or sawmills. He sold the up to 15,000 cubic metres of bark to garden centres or farmers and, if there was no demand, he simply composted it. But then he came up with the ingenious idea of processing the bark into briquettes. The settlement of Beniwood AG brought Erlenhof a step closer to a closed timber life cycle: from sawing and timber construction to bark utilisation.

On 25 May 1996, company director Leonhard Lehmann suffered a stroke. Although he survived and his mind remained sharp, continuing in company management was unthinkable. For the first time in its history, the Lehmann’s family-run business faced a crucial question: what next?
 

At that time, Ruth and Leonhard Lehmann’s children were still in education. Katharina was studying Economics at the University of St. Gallen (HSG), Leonhard V was doing his carpentry apprenticeship and Regula was training to become a kindergarten teacher. What’s more, the company was facing major challenges. The real estate crisis was still being felt, the sawmill was operating at a loss despite or because of high investments and large-scale DIY superstores were springing up all across the country, threatening Lehmann’s timber market in Gossau. Who could and should take the reins?

The patron’s stroke caught the company off-guard. Trusting that she wouldn’t have to make decisions all on her own, 24-year-old Katharina Lehmann said that she would take on the responsibility. She had grown up at Erlenhof, knew each and every employee and was familiar with the company’s strengths and weaknesses. But she was also aware that she was too young and inexperienced to be the ‘boss’, which is why she distributed responsibility among various key personnel.

The patron’s stroke caught the company off-guard. But this unfortunate situation revealed the family-run business’s greatest asset. The 66 employees of Leonhard Lehmann AG pulled together, just like every family does when faced with adversity. It now became apparent that the concept of a family-run business extended far beyond the Lehmann family.

Trusting that she wouldn’t have to make decisions all on her own, 24-year-old Katharina Lehmann said that she would take on the responsibility. She had grown up at Erlenhof, knew each and every employee and was familiar with the company’s strengths and weaknesses. But she was also aware that she was too young and inexperienced to be the ‘boss’, which is why she distributed responsibility among various key personnel.

As operators of SMEs, Leonhard Lehmann and Hermann Blumer faced similar challenges: limited capital and high investment needs. Lehmann Gossau’s state-of-the-art sawmill wasn’t yet profitable, and Hermann Blumer urgently needed new partners for his indebted company, Blumer AG based in Waldstatt.

With Leonhard Lehmann AG’s acquisition of Blumer Elementtechnik AG, Erlenhof gained extensive expertise and excellent prefabricated construction specialists all in one go – particularly in Richard Jussel, who was appointed Head of Timber Construction. The new prefabricated construction hall was opened at Erlenhof in 1999 and also became the new workplace for Blumer’s former employees. In 2000, the two companies merged to form Blumer-Lehmann AG.

There was mutual respect and appreciation. Since building the Säntispark in 1985, Leonhard Lehmann and Hermann Blumer had worked together regularly, often exchanging ideas in Lignum, an industry association. Both faced similar challenges as operators of SMEs: limited capital and high investment needs. Lehmann Gossau’s state-of-the-art sawmill wasn’t yet profitable, and Hermann Blumer urgently needed new partners for his indebted company, Blumer AG based in Waldstatt.

Mr Blumer turned to Leonhard Lehmann. But, after the initial talks, Leonhard Lehmann suffered a stroke. Katharina Lehmann, who was still a student at that time, took over from her father and continued the talks that led to Leonhard Lehmann AG’s acquisition of Blumer Elementtechnik AG in 1997. As a result, Erlenhof gained extensive expertise and excellent prefabricated construction specialists all in one go – particularly in Richard Jussel, who was appointed Head of Timber Construction.
 

Silo construction was a niche market and the competition from Germany was strong. So Jakob Frischknecht from Schmid, a small silo construction company based in Wattwil, set out to find a strong partner and ended up at Erlenhof.

In 1999, silo construction began at Erlenhof. Mr Frischknecht initially managed this new business segment alone, only calling on Blumer Lehmann employees for construction work. The first time was to help build a 60 m³ salt silo in Oberwil, in the Canton of Basel-Landschaft.

Blumer Lehmann’s first international appearance at Expo 2000 in Hanover was still overshadowed by Peter Zumthor’s famous ‘Swiss Sound Box’. Nevertheless, Blumer Lehmann demonstrated its expertise in timber construction with several of the 11 modular multi-service complexes.

Two years later, at Swiss Expo. 02, Blumer Lehmann received a larger stage – with three projects, including the ‘Nature and Artificiality’ buildings at the Arteplage in Neuchâtel. Such complex forms would be almost impossible without prior investment in new 3D planning tools.

A fire had already broken out at Erlenhof in 2003 – in the planing mill. One year later, the pellet plant went up in flames. Two events like this would push a family-run business like Blumer Lehmann to its financial limits. It would be five years before funds could be raised to rebuild the planing mill.

And as if the fires weren’t unfortunate enough, a 150 m³ silo in Ostermundigen, in the Canton of Bern, collapsed in June 2004. This was caused by a series of unfortunate events – from fungal infestation of the timber supports to the silo only being filled on one side. Blumer Lehmann took responsibility and replaced the silo at its own expense. Additionally, Blumer Lehmann set up its own silo construction service department, which thereafter inspected, maintained and serviced silos at regular intervals.

When the Cantons of St. Gallen and Thurgau announced an architectural competition for the new cantonal school in Wil, they requested a timber construction. This was a bold decision for a school that would accommodate 600 students. Frauenfeld-based Staufer & Hasler Architekten won the competition in the end, while Blumer Lehmann took the lead in timber construction.

This showcased Blumer Lehmann’s expertise in prefabricated construction. With a building volume of 77,435 m³, Wil Cantonal School became one of the largest timber structures in Switzerland.

In 2005, Blumer Lehmann acquired Wey Modulbau AG, a company based in Villmergen, and thus gained extensive expertise in the field of modular construction all at once.

The unfortunate collapse of a silo in 2004 barely diminished trust in Blumer Lehmann’s silo construction operations. After several successful projects in Germany, Austria and Switzerland, Blumer Lehmann set new standards in silo construction in 2007 in Sterzing, South Tyrol:

Three silos with a capacity of 600 m³ each, making this the largest silo facility in Europe. But it wasn’t just the size that placed high demands on the statics; it was the bulk material – marble granulate – too. This is up to 70% heavier than salt and must be stored such that it is dustproof, which is why Blumer Lehmann lined the three hoppers with chrome steel sheets.
 

It was a stroke of luck for Blumer Lehmann that, in Tokyo, a brilliant architect dedicated himself entirely to wood: Shigeru Ban. In 2008, he built the famous Haesley Nine Bridges Golf Clubhouse in South Korea, which became the first collaboration between Shigeru Ban and Blumer Lehmann.

From the roof to the load-bearing, Gothic-inspired columns – everything was bent, curved and Free Form. Blumer Lehmann invested in a new CNC system, in a building for this machine, and in a wealth of knowledge, entering the stage of global architecture.

If you’ve read Blumer Lehmann’s history up to this point, you’ll know that success is the result of one thing, and one thing only: hard work. But sometimes it doesn’t hurt to have luck on your side either. Or to be in the right place at the right time. In any case, it was a stroke of luck for Blumer Lehmann that, on the other side of the world, in Tokyo, a brilliant architect dedicated himself entirely to wood: Shigeru Ban.

In 2008, he built the famous Haesley Nine Bridges Golf Clubhouse in South Korea, which became the first collaboration between Shigeru Ban and Blumer Lehmann. After all, there weren’t many timber construction companies with the technological and staffing resources needed to implement Mr Ban’s daring design.

From the roof to the load-bearing, Gothic-inspired columns – everything was bent, curved and Free Form. There were no standard solutions. Blumer Lehmann invested in a new CNC system, in a building for this machine, and in a wealth of knowledge, entering the stage of global architecture.

The collaboration with Shigeru Ban continued in 2012 for the new Tamedia building in Zurich, which was followed in 2019 with the joint construction of the Swatch headquarters in Biel: the iconic ‘Caterpillar’. In the intervening years, Shigeru Ban won the 2014 Pritzker Architecture Prize.

Around ten years after building the golf clubhouse, we found ourselves working for the Haesley Nine Bridges Golf Resort once more. From 2018 to 2022, six more extraordinary buildings were constructed: a learning centre, a recreation centre, the underground ‘Grand Hall’ foyer complete with a restaurant and the three Condo A apartment buildings.

Blumer Lehmann’s planing mill employees had been working in temporary facilities since the fire in 2003. Nevertheless, all the signs were pointing towards growth in the timber industry. The sawmill had already been kitted out with a new sorting system back in 2004, and, two years later, the log inspection site was completely revamped to optimise workflows there too.

Since then, round timber had only been delivered in trunks measuring 5 metres long. At the same time, planning began for a more efficient planing mill with a band resaw and integrated cross-cutting milling machine, plus a packaging and labelling machine.
 

Visitors to the Tamina Therme building at the prestigious Grand Resort Bad Ragaz hotel were seeking one thing, and one thing only: peace at long last. And this need was reflected in the light, airy architecture of the thermal baths.

The timber construction rests on 115 columns that were made by Blumer Lehmann, from sawing the 2,200 native spruce trees to the precast elements with preinstalled oval windows. Prefabrication meant the construction time was halved to 13 months.

To grow, you need energy. This is particularly true of Beniwood AG’s pellet production operations, which were now producing around 10,000 tonnes of pellets from Blumer Lehmann’s residual timber.

Blumer Lehmann founded Lehmann Energie AG in 2010 and put its very own biomass power plant into operation. This not only made Erlenhof self-sufficient in terms of energy supply; it also fed electricity into the grid for around 1,200 nearby households. Blumer Lehmann had finally closed the timber life cycle. Wood was harvested in the forest and processed into construction materials at Erlenhof, residual timber was converted either into heat carriers or electricity, and resulting CO₂ emissions were, in turn, captured by trees in forests.
 

In 2011, Blumer Lehmann’s Silo Construction division became independent in terms of both its service portfolio and legal structure: with its own staff, international sales structures and a site in Germany – initially in Untermeitingen and later in Klosterlechfeld.

For the first time ever, Blumer Lehmann built a fully automated complete silo construction facility, including brine and conveyor systems, a pneumatic switch stand and hydraulic sliders for salt extraction. The silo builder relied on long-standing partners for automation and control matters. Blumer Lehmann was now able to operate on the market as a complete solutions provider, and customers could receive fully automated winter maintenance systems from a single provider if needed.

Zurich has been growing since the late 1990s – and then some! The city’s population increased by 85,000 inhabitants between 2000 and 2023 alone. But one thing that’s lagged behind housing construction is school construction, which is why, in 1998, the city developed a modular system where prefabricated timber modules could be combined to form classrooms.

Thanks to its acquisition of Wey Modulbau AG based in Villmergen in 2005, Blumer Lehmann possessed the expertise to take over production of the second generation of these Zurich ZM10 modules in 2012. Each working day, two to three ZM10 modules were preassembled in the factory, then 10 to 20 modules were subsequently installed on the construction site. Depending on the project complexity and size, final assembly took between one week and five months.  

Blumer Lehmann acquired Beniwood AG. The newly acquired business division, Lehmann Pellets AG, either processed all the residual timber – sawdust, wood shavings and bark – into carbon-neutral heat carriers such as pellets and bark briquettes or converted it directly into heat and electricity in the new power plant.

The timber life cycle at Erlenhof was closed, with residual timber products supplementing the range of timber solutions on offer. Urban Jung, the long-standing manager and driving force behind Blumer Lehmann’s Timber Industry Division, thus reached another milestone. His motivation was further advancing timber as a raw material, developing new products, striking a balance between craftsmanship and industry and, in particular, generating energy from residual timber.

The next project that architect Shigeru Ban, Hermann Blumer and Blumer Lehmann all collaborated on was Tamedia’s office building at the heart of Zurich. The glass frontages allowed an unobstructed view of the exposed, load-bearing timber construction.

Thanks to special hardwood inserts, precise CNC production and ingenious assembly, Switzerland’s first-ever seven-storey timber structure and the first flagship building incorporating urban timber construction on a large scale was created.

Free Form is not based on norms and standards. Instead, it is guided by architects’ designs. In 2014, Blumer Lehmann consolidated its Free Form expertise in Timber Code AG, its very own assembly hall on Bischofszellerstrasse in Gossau and a TW-Mill high-tech milling machine from TechnoWood, which mills raw timber measuring up to 27 × 5.5 × 1.35 metres into components with complex geometries.

Timber Code AG’s intense startup phase left its mark, resulting in reintegration into Blumer Lehmann. Nevertheless, the path for Free Form had been paved, and more Free Form projects followed.

Timber Code AG’s intense startup phase left its mark, so the company was reintegrated into Blumer Lehmann. Nevertheless, the path for Free Form had been paved. And it didn’t take long for star architect Shigeru Ban to come knocking again.

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‘We don’t want to impose designs on architects. Instead, we try to accommodate their ideas and make them buildable.’ Kai Strehlke, a Free Form specialist at Blumer Lehmann since 2015

Thanks to new building regulations, timber constructions became ever larger, and large timber complexes were also emerging in residential construction. The Bildweiher housing complex in St. Gallen was one example of this.

At that time, multi-storey residential buildings were hugely popular due to their good energy values, healthy indoor climate and natural aesthetics, and became an integral part of Blumer Lehmann’s portfolio.

When the listed Kobesenmühle residential building in Niederhelfenschwil, built in 1698, was to be sensitively renovated in 2015, Blumer Lehmann was awarded the contract for the timber construction work.

Hardly any new timber was used. Instead, the existing timber – whether new or old – was left untreated and was cleaned, reconstructed where necessary, supplemented and replaced at certain points, particularly on the north facade, in the arcade and on windows and doors. The finished work was included in the Canton of St. Gallen’s Heritage Conservation ‘Exemplary Renovations’ documentation.

‘The building lies in the meadow like open accordion bellows.’ This journalist’s comparison aptly described the extension to the Théâtre de Vidy in Lausanne, which was designed by architect Yves Weinand in a folded plate structure.

Mr Weinand is Director of IBOIS, the Laboratory of Timber Construction, at the École Polytechnique Fédérale de Lausanne (EPFL), which has been conducting research into folded plate structures for years now. This highly instructive collaboration was a good example of how Blumer Lehmann works together with ETH Zurich, Empa, the University of Stuttgart and other educational institutions, further developing expertise in timber processing in both research and practice.

Under extreme conditions, Blumer Lehmann built a three-storey hospitality area with capacity for 1,800 people in Zurich in 2018 for the first-ever Formula E race.

The Neue Zürcher Zeitung described the first Formula E race in Zurich as ‘an electromobility showcase’. Spectators in the stands didn’t need to cover their ears – the race cars ran on electricity. Long before the race, a competition of a different kind took place: who would build the three-storey hospitality area with capacity for 1,800 people? Companies from the steel, scaffolding, tent and timber construction sectors all put their names into the hat. The ‘disciplines’ that applicants competed on included cost, assembly and dismantling speed and potential for reuse.

Blumer Lehmann won the competition. So, in 2018, the Gossau-based company worked under extreme conditions to build the structure in Zurich. The location of the hospitality building was the busy Mythenquai in Zurich’s Enge quarter, so the construction process (which didn’t stop traffic) became a logistical masterpiece. After the race, the temporary construction was transported to Saudi Arabia for the next Formula E race.

With the help of parametric planning and high-precision production, logistics and assembly, one of Switzerland’s most spectacular buildings was constructed: the Free Form timber construction for the Swatch headquarters in Biel.

The building, designed by architect Shigeru Ban, also marked the end of his tremendous timber construction career. In 2020, Richard Jussel, the long-standing Head of Timber Construction, handed over the reins to younger colleagues – three, to be exact. Martin Looser took over the Free Form and International divisions, Markus Rutz the Timber and Modular Construction divisions in Switzerland, and Lukas Osterwalder the Timber and Modular Construction divisions in Germany, Austria and Luxembourg. The split into three divisions reflected the requirements and expectations that Blumer Lehmann places on timber construction.

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‘I have a great deal of respect for the Blumer Lehmann team. They have traditional craftsmanship skills and yet also work with state-of-the-art 3D modelling and CNC machines.’ Shigeru Ban

Blumer Lehmann can handle silos, modular constructions, complete systems and automation. When you combine all these areas of expertise, what you get is a fully automated modular silo system.

In 2019, Blumer Lehmann built the largest-ever silo facility to date in Chur for the Federal Roads Office (FEDRO), with a salt storage volume of 2,300 m³, brine production capabilities, an operations room with a kitchen and toilet, and an underground return conveyor.

The facade made of Swiss larch wood does more than just protect the four modular silos. It looks truly chic too. Further examples of silo construction aesthetics can be found in modular silos in Fribourg, Canton of Fribourg; Olivone, Canton of Ticino and Le Sépey, Canton of Vaud.

What if Blumer Lehmann were to see itself as an international company – with roots and headquarters in Switzerland and subsidiaries abroad?

In 2019, Blumer Lehmann established its first foreign sales location in Luxembourg. In 2021, a sales and project development office followed in Grafschaft near Bonn and a rented assembly hall was commissioned in Grossenlüder, Hesse, in the heart of Germany. This is where both modular and temporary buildings for the German and Scandinavian markets would henceforth undergo final assembly.

Projects didn’t take long to materialise. In 2022, a school extension was opened in Schondorf, Baden, and a new school building with a modular timber design was built in Dresden. Business was booming, and Blumer Lehmann decided to build its own, larger assembly hall in Steinau an der Strasse, not far from Grossenlüder. With the acquisition of oa.sys GmbH, an Austrian firm based in Alberschwende, Vorarlberg, including its production capacities, Blumer Lehmann completed its presence in Germany, Austria and Switzerland.

The St. Gallen theatre needed to undergo renovation and expansion. To ensure the company and St. Gallen’s theatre goers wouldn’t be without a venue during the construction work from autumn 2020, Blumer Lehmann built the temporary UM!BAU structure with everything a theatre needs:

a box office and cloakrooms, a foyer with a bar, and an auditorium complete with stage, orchestra pit and platform. The temporary building served as a theatre for three seasons, after which careful dismantling work began in November 2023. In January 2024, the first spruce and fir wood elements began their 300-kilometre journey to Ingolstadt, Bavaria, where the Stadttheater was also due to undergo renovation.

In 2022, the 27-metre-tall, fully automated high-bay warehouse for sawn timber went into operation at Erlenhof. The hall, with approximately 900 storage spaces, offers ideal conditions for storing timber thanks to temperature control and humidity regulation.

Timber storage and retrieval in the warehouse is fully automated thanks to a programmable storage and retrieval unit – a one-of-a-kind solution in the Swiss timber industry.

‘We are Blumer Lehmann’ – this statement united all of the Lehmann Group’s companies and sites under a common brand: Blumer Lehmann.

The standardised brand identity simplified the corporate structure and communication both externally and internally, while also highlighting the wide-ranging expertise along the timber life cycle – consolidated under one roof.

From 2018, Blumer Lehmann turbocharged investments in the timber industry – starting with relocating the Loobach waterway and building a new access road. After the high-bay warehouse for sawn timber went into operation in 2022, a fully automated bagging line for pellets and litter for small animals followed in 2023.

The sawmill was operating at full capacity, reporting a record cutting volume of around 174,000 solid cubic metres of round timber in 2022/2023 – one third more than in 2019.

In tandem with this development, the capacity utilisation of the planing mill (which is once again operating in two shifts) increased, returning to two-shift operation. Additionally, the sorting and finger-jointing mill opened in 2020 enabled sorting of sawn timber by quality and dimensions. With three newly built halls, timber construction capacities for timber framing and element and module production were also expanded and processes were optimised.

Areas of expertise that had previously been outsourced returned to Erlenhof, and a new laminating facility will further extend the value chain from 2025. The Swiss site is also recording growth in staffing terms. With the acquisition of the Hächler Group’s Timber Construction division in April 2025, 20 experienced timber construction professionals will join Blumer Lehmann’s team at their current workplace in Neuenhof, near Wettingen.

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‘Then the round timber is delivered here, the sawn timber produced from it is processed into panels and beams in the laminating facility, and finally installed directly into our modules’, Urban Jung, Manager of the Timber Industry Division
 

150 years ago, the Loobach waterway was the reason why Leonhard Lehmann I built his sawmill here at Erlenhof, laying the foundations for Blumer Lehmann’s history. However, the growth the company has experienced in recent years has pushed the site to its limits. Blumer Lehmann has had to rent halls and offices all over the region.

While Katharina Lehmann drove forward the integrated value chain strategy – with holistic timber solutions from Erlenhof – the company premises became too small. And the Loobach waterway to the north prevented expansion of the industrial utilisation zone. Only with considerable bureaucratic and construction efforts was it possible to successfully move the stream northwards, thus securing the site’s future. The new head office draws a line under all these investments, bringing together what belongs together. And with the head office, employees, partners and visitors alike have a new place to both work and come up with fresh ideas.