Troldtekt A/S – the story

Photo: L. Hammerich

A business is born

The year is 1855, and the businessman J. C. Seidelin is ready to open the doors of Aarhus’s first specialist builders’ merchant. The shop J. C. Seidelin is situated on Fredens Torv 12 in central Aarhus, and stocks articles such as bricks, roofing tiles, slates, cement and pipes. Moreover, the shop is the first to start importing building supplies from abroad directly to its premises in Denmark’s second-largest city.

Seidelin’s business does a brisk trade and, by the standards of the times, is relatively large. Between 1873 and 1882, annual turnover is around 100,000 kroner, and the shop holds stock with a value of about 10,000 kroner. This should obviously be seen in light of what money was worth back then, when a pound of butter, for example, cost two marks (one mark was worth approx. 0.33 øre), which also bought you about 20 eggs. Those were the days ...

Also, new days are dawning for J. C. Seidelin. In 1870, Seidelin, who has a reputation for being a good businessman of considerable integrity, is appointed managing director of Aarhus Privatbank, the first private bank in Aarhus, which later became Provinsbanken. For several years, he runs his business concurrently with the job of bank director, before selling it in 1884 to Louis Hammerich. This marks the end of the Seidelin era – and the start of the L. Hammerich era.

Photo: Louis Hammerich

A growing business

L. Hammerich Forretning i Bygningsartikler (L. Hammerich Building Supplies) is what the shop J. C. Seidelin comes to be called after Louis Hammerich takes over the shop from the founder. Louis Hammerich has just finished his apprenticeship with the well-known Aarhus businessman Hans Broge, who gives him an excellent reference.

When Louis Hammerich takes over business, turnover starts growing steadily, almost doubling within its first year. However, the results make little impression on the young man. This can be seen from the first of the annual reports he writes in his neat hand in 1884. With some modesty, he says: "Even though I had no knowledge of the business which I acquired, I was extremely fortunate in the first year to see an increase in turnover from 70,000 to 120,000 kroner."

The company continues to expand, and to meet the growing demand, in 1894 L. Hammerich Forretning i Bygningsartikler purchases the space "Fru Kaspersens Plads" in Grønnegade in Aarhus. From here, the business extends its product programme to also include imported goods. At the turn of the century, the business boasts turnover of no less than 300,000 kroner – an auspicious start to the 1900s for the Aarhus-based trading company.


In 1927, L. Hammerich moves to new and larger premises in Grønnegade, which include a showroom for displaying the new construction materials of the times.

A limited liability company is formed

L. Hammerich Forretning i Bygningsartikler becomes a limited liability company immediately before the outbreak of the First World War. The company must brace itself for the challenges ahead at a time of headwinds for the building industry.

At the start of the twentieth century, both demand and turnover are increasing for L. Hammerich Forretning i Bygningsartikler The business’s steady growth fuels a growing desire to transform the company into a limited liability company. On 29 September 1911, A/S L. Hammerich & Co. is formed with registration number 645 – and a share capital of 200,000 kroner.

The company is geared to facing the challenges lurking just around the corner. The First World War puts a stop to imports and leads to stagnation within the building trade. Commodity prices increase three or fourfold, and A/S L. Hammerich & Co. sees a sharp drop in turnover. On the other hand, the company enjoys the boom which comes after the end of the war.

In 1920, turnover tops one million kroner, despite the fact that, from 1922 to 1925, commodity prices fall to a third of their wartime level.

In 1923, Paul Hammerich, the third of Louis Hammerich’s six sons, is employed as a manager in the company after commercial training in Denmark and abroad. The plan is that he will take over as managing director after his father as part of a generational transition. In 1927, Paul Hammerich is appointed co-managing director with his father. In the same year, L. Hammerich builds new and larger office premises and warehouse facilities at Grønnegade 57-59. The property at Fredens Torv 12 is sold, and the entire business moves to Grønnegade. The move marks the start of a new chapter for the now just over 70-year-old company ...

Growth spurt in western Jutland

In the 1930s, A/S L. Hammerich & Co. spots a new business opportunity in the form of Danish wood wool and a factory in Troldhede in western Jutland, where both raw materials and labour are readily available.

Louis Hammerich’s death in 1931 followed by that of his son Paul only a few years later marks the end of an era. However, a new chapter in the company’s history starts with Aage Filtenborg as managing director. He has been with A/S L. Hammerich & Co. for many years, and it is largely thanks to him that, in 1935, the factory A/S Troldhede Pladeindustri in Troldhede in western Jutland catches the company’s attention.

Where in the 1850s there was only heathland, and in 1900 spruce and pine plantations, in 1935 a modern factory has shot up for manufacturing the only Danish wood fibreboard, Danatex, and Troldtekt wood wool panels. A/S Troldhede Pladeindustri is situated in an area where land is cheap, labour is plentiful and the raw materials are right on the doorstep. The combination of quality and price has taken on a new importance in the wake of the crisis in the construction industry in the early 1930s, and there is now a widespread need to build well – and inexpensively.

Early on, A/S L. Hammerich & Co. recognises the potential of this modern building material, which combines properties such as strength, good insulation and lightness. Over a number of years, the company acquires the factory and ups production. This is an extremely positive development for the local area – not least the local population. They are spared unemployment, and instead enjoy the prospect of useful work and a weekly income of about 10 kroner.
New times are indeed arriving on the heathlands of western Jutland. And in 1936, the great news is illustrated in a Troldtekt advert which has not been matched since.

Danish lads show their pluck during occupation

In 1939-1945, creative transport solutions keep production up and running at A/S L. Hammerich & Co., while the management turns a blind eye to the Resistance fighters "borrowing" the company’s vehicles.

In the late 1930s, business is flourishing for A/S L. Hammerich & Co. Due to an extremely high demand for Troldtekt, the company is compelled to add a further 7,500 square metres of storage facilities. Its faith in growth and development cannot be cowed by the prospect of a world war.

Aage Filtenborg is running A/S L. Hammerich & Co. when Denmark is occupied by Nazi Germany, and the company soon starts to feel the impact of the tough wartime conditions. The war puts production on hold, and a constant lack of supplies and transport problems call for some creative thinking. Instead of trucks, horses are used to carry Troldtekt panels across the heathland to the nearest railway station. Having overcome the problems with the "new" form of transport, production resumes after a year-and-a-half-long stoppage. Despite the adverse trading conditions, A/S L. Hammerich & Co. posts a turnover of 2.6 million kroner in 1941.

During the occupation, A/S L. Hammerich & Co. is one of the companies in Jutland with links to the Resistance movement, and the management turns a blind eye when one of the company’s vehicles is "stolen", something which happens quite frequently. And when the truck is "surprisingly" found parked close to the offices in Grønnegade in Aarhus, there is every chance that the tyres have been changed. Tyres, like everything else, are in short supply during the war, and could be in such poor state that the "thief" could be forced to steal tyres or even complete wheels in order to execute his assignment.

Peace and progress

For A/S L. Hammerich & Co., the 1945-1955 period is marked by a temporary slowdown on the European market. However, this is offset by growth closer to home in Denmark, and the company is running on all cylinders as it celebrates its centenary in 1955.

In 1945, the war is finally over, and Denmark breathes a collective sigh of relief. However, A/S L. Hammerich & Co. has to accept that the end of the war is not all good news for the business; Germany is split in two, and the company loses valuable dealerships. After considerable effort, A/S L. Hammerich & Co. fortunately finds new factories in West Germany, Portugal and Italy and starts rebuilding its strong market position.

Back home in Denmark, the post-war years are marked by rapid growth. The war has created a pressing need for reconstruction and new building work, putting A/S L. Hammerich & Co. in a favourable position. At the factory in Troldhede, the raw materials are close by and there is ample labour. Sales of Troldtekt therefore increase markedly in the following years. Celebrating its centenary in 1955, the enterprising business posts an annual turnover of approx. 8 million kroner. An impressive result, and one which would probably have been beyond Louis Hammerich’s wildest dreams when, in 1884, he took over the shop in Aarhus and named it L. Hammerich Forretning i Bygningsartikler.

Building boom, streamlining and prosperity

In 1956-1969, the Danish economy is booming ahead, and for the first time ever the value of industrial exports exceeds that of agriculture. Troldtekt A/S, which back then is still called A/S L. Hammerich & Co., makes the most of the upturn and explores new ideas for more efficient production methods through greater mechanisation and the specialised division of labour.

In 1964, A/S L. Hammerich & Co. installs Denmark’s first fully automated plant for manufacturing wood wool panels in Troldhede. At the company’s warehouse on the corner of Vestre Ringgade and Daugbjergvej in Aarhus, palletisation and fork-lift trucks are introduced. This is a big step for a builders’ merchant used to handling everything individually. The rationalisations save time – and cut costs.

Developments at A/S L. Hammerich & Co. are part of Denmark’s second industrial revolution, inspired by the ideas of the car manufacturer Henry Ford and the engineer F. W. Taylor. They involve splitting up the work processes and calculating the optimum work routines for each function. At the same time, machines take over the simple routines. In this way, far more units can be produced at the factories with the same number of employees and in a shorter space of time.

For A/S L. Hammerich & Co., the development makes it easier to sell whole pallets of construction materials, and in 1964 turnover tops 20 million kroner.

In the late 1960s, Grafisk Tegnestue, a firm of graphic designers in Aarhus, worked with A/S L. Hammerich & Co. on the design of a new, one-coloured logo – which was what printing technologies back then could handle. The logo combines the initial “H” with an abstract depiction of a ceiling which, adhering to the 1960s’ logo ideal, draws attention to the company’s product. The bold graphic style in a subdued colour signals a reliable and solid company in 1964.

Growth despite crisis

Two oil crises, currency turmoil and inflation dominate the Danish economy in the 1970s. Nevertheless, Troldtekt, which still goes by the name of A/S L. Hammerich & Co., manages to invest in new facilities and stimulate growth.

In 1974, A/S L. Hammerich & Co. moves its storage facilities on Vestre Ringgade to a 50,000-square-metre plot on P. O. Pedersens Vej in Skejby, a suburb in the north of Aarhus. With a modern warehouse stretching 117 metres in length and 42 metres in width, and a total investment of 9 million kroner, the company is geared for the future.

Drama in Troldhede
The 1970s are also an eventful decade at the company’s production plant in Troldhede. In 1974, the company adds a new extension to the factory, while strengthening its marketing efforts. In 1977, however, an intense fire erupts at A/S Troldhede Pladeindustri, and the old factory section is consumed by flames, the result of arson. Fortunately, the factory is well-insured, which means it is soon possible to resume production.

From grey to white cement
In the late 1970s, A/S L. Hammerich & Co. acquires the know-how to produce wood wool based on white cement.  Until then, panels have been produced using grey cement only, but the white cement makes it possible to produce “light” Troldtekt panels. It also paves the way for using Troldtekt in, for example, schools and institutions, which welcome the light-coloured wood wool.


Market-leading position after drastic economic measures

The crisis in the construction industry in the 1980s causes A/S L. Hammerich & Co. to trim its organisation and product range. It proves to be the right strategy, and the company is more than one step ahead of its competitors on the cusp of the new decade.

On 9 October 1980, A/S L. Hammerich & Co. celebrates the 125th anniversary of the company’s foundation with a well-attended reception and a staff party at Hotel Atlantic in Aarhus. To mark the anniversary, selected tiles are sold at 1855 prices for the rest of the month. The company still stocks a wide range of building materials in addition to Troldtekt – but this is about to change.

Effective new strategy

The oil crisis leads to a crisis in the construction industry in the 1980s, and demand for building materials falls. The Troldtekt management is resolute: It trims the organisation, says goodbye to its tradesmen customers and now supplies exclusively to wholesale customers. At the same time, roofing tiles, floor tiles and traditional building materials are phased out. On the other hand, the management invests in a more efficient drying oven as well as new cutting, bevelling and painting plant. The initiatives put Troldtekt in a strong market position.

Asbestos problems and new materials

During the 1980s, it becomes clear that asbestos and karlit ceiling panels were a really bad idea. In 1984, the newspaper Aarhus Stiftstidende writes: “Tear down the fibre-shedding karlit ceiling panels and replace them with wood wool instead. It will improve the indoor climate immediately, and any symptoms of illness disappear.” The article stimulates further demand for Troldtekt. In addition to industrial and agricultural buildings, the panels are now being used to an increasing extent for ceilings in schools, offices and institutions. As a result, Troldtekt is a step ahead of its competitors as the 1990s come hurtling towards us.

Technological advances gain momentum

For A/S L. Hammerich & Co., as it is still known, the 1990s are a dynamic decade of production optimisations and new solutions, combined with a strong focus on indoor climate and the environment.

The initiatives have a tangible impact on business during the last ten years of the millennium. The general technological improvements in Danish industry and increasing levels of activity in the construction sector have a positive impact on production in Troldhede, reflected among other things in streamlined working processes and new machinery.

From heavy lifts to light machine Work
Aided by the new machines, employees now have an easier time handling the timber, which previously involved a lot of heavy lifting and unhealthy working positions. Planes which in the past were operated manually are now machine-controlled. And the machines are busy, bringing good acoustics to schools and industrial and agricultural buildings. Among other things, L. Hammerich & Co. develops acoustic panels featuring diffuse ventilation for livestock housing in collaboration with Schou Ventilation. The product is designed to ensure that buildings are well-ventilated without exposing the animals to draughts.

Suitable for living rooms
In 1997, Troldtekt is the first ceiling product to carry the Indoor Climate label from Danish Indoor Climate Labelling. The labelling documents that Troldtekt releases no hazardous particles or gases, but contributes to a healthy indoor climate. Two years later L. Hammerich & Co. receives Midtbank’s environmental prize and 2,000 kroner for its work with environmental certification. The newspaper Ringkjøbing Amts Dagblad reports that the company will continue to flourish in the new millennium, catering to the needs of the political consumer who wants to make environment-friendly choices. And it was right.

Troldtekt timeline

J. C. Seidelin opens the first dedicated store for building materials at Fredens Torv in Aarhus.

Louis Hammerich takes over the business and expands the range to include wholesale products and begins to import building materials from abroad. 

L. Hammerich Specialforretning i Bygningsartikler is renamed Aktieselskabet L. Hammerich & Co. The public limited company has registration number 645 and is thus one of the oldest surviving public companies in Denmark. 

The business has grown, and A/S L. Hammerich & Co. moves into modern new premises in Grønnegade in central Aarhus. Poul Hammerich, Louis’s son, takes over management of the company.

A/S L. Hammerich & Co. acquires A/S Troldhede Pladeindustri in Troldhede. Fibreboard and the cement-bonded wood wool Troldtekt® panels are manufactured here, and a registered trademark is acquired in 1936.

Poul Hammerich sets up the ‘Grosserer L. Hammerich og Hustru Ellen, f. Lisbergs Legat’ foundation to support families and staff. Poul Hammerich dies at a young age, but the foundation is subsequently realised.

Svend Hammerich joins the company management and helps re-establish the company’s position following the Second World War.

The fourth generation of the Hammerich family, Peter Hammerich, joins the company management.

The product range is extensively restructured, with a 100 per cent focus on Troldtekt and a few trade goods. All warehouse facilities are moved to Troldhede, while sales and administration are moved to new offices on Klamsagervej, Åbyhøj. Peter Hammerich leaves the company.


Thorkild Bjerglund Andersen, who has been on the company’s board of directors since 1973, purchases A/S L. Hammerich & Co.

A/S L. Hammerich & Co. moves to the sawmill Aarhus Savværk’s former premises on Søren Nymarks Vej in Højbjerg.


Running out of space again, A/S L. Hammerich & Co. moves to the old Østergaard manor in Malling, which Thorkild Bjerglund Andersen has renovated while farming the adjoining land. Huge investments are made in streamlining and modernising production in Troldhede.

The new millennium marks the beginning of a period of strong product development. Troldtekt is no longer just acoustic panels, but acoustic solutions with integrated lighting, sound, ventilation and decoration.

A/S L. Hammerich & Co. and A/S Troldhede Pladeindustri merge under the name A/S L. Hammerich & Co., with sales and administration in Malling and production in Troldhede.

Thorkild Bjerglund Andersen’s heirs take over the company and carry on the family-owned enterprise under the management of a professional advisory board.

Following a business succession, A/S L. Hammerich & Co. moves to more contemporary premises on Sletvej in Tranbjerg outside Aarhus, and the company name is abbreviated to L. Hammerich A/S.

The 75th anniversary of the production of Troldtekt acoustic panels is marked by changing the company name to Troldtekt A/S. Troldtekt receives the Danish Building Industry Environment Award the same year for its focus on the environment and sustainability throughout the product’s entire life cycle.

Troldtekt qualifies for Cradle to Cradle certification in the silver category and prepares a roadmap for developing Cradle to Cradle quality at Troldtekt through to 2022.

The CSR Foundation awards Troldtekt A/S the CSR Awards’ Strategy Prize for its solid and strategic approach to CSR and for having established CSR in all parts of the business, including at executive level and in the business strategy.

Troldtekt Deutschland GmbH is established in Hamburg, the company’s first foreign subsidiary. The strategic focus on neighbouring export markets is followed up by a significant expansion of production capacity in Troldhede.

The company’s second foreign subsidiary, Troldtekt AB, is established in Malmö in Sweden, and production capacity is further expanded.

Troldtekt's production capacity is doubled with the opening of a new 13,000-square-metre production line in Troldhede in western Denmark.

Troldtekt becomes part of the Kingspan Group, an Irish company that supplies high-quality building materials to the global construction industry. At the same time, Troldtekt decides to double its production capacity with an additional factory in Troldhede.