A tale of stone

Our heritage

A tale of stone



80th birthday

This year, at ROCKWOOL Group we celebrate 80 years since our founders first produced stone wool in Hedehusene, Denmark, where we are still headquartered today. Continuity like this is unusual in the business world. Why have we endured so long? It’s because ever since we were founded, we’ve had one single-minded purpose: unlocking the unique strengths of stone to enrich modern living. Everything we do is organised around this ambition.

RW-Doense Production facility, Factory


Health and safety of ROCKWOOL products confirmed

In 2001, the International Agency for Research on Cancer (IARC) classified rock (stone) wool insulation as Group 3: not classifiable carcinogenic in humans. The IARC (the World Health Organisation’s cancer research institute) re-evaluated the thousands of existing health investigations on stone wool in production or in use.

To be updated


Further ROCKWOOL Group expansion

In 2000, a factory in Malacca, Malaysia was acquired and a greenfield factory in Caparosso in Spain taken into operation. The year 2004 saw the purchase of the Hungarian Isolyth factory and buildings were acquired in Vyborg in Russia with a view to building manufacturing plant. In 2005, the decision was taken to build a greenfield plant in Croatia. A year later, in 2006, the new factory in Cigacice, Poland was inaugurated, and in 2008, the decision to build a new factory in Gujarat in India was taken.

RockWorld imagery, products with life, oslo opera, walking roof, architecture


Focus on energy efficiency

The Kyoto protocol was the first agreement among nations to mandate country-by-country reductions in greenhouse gas emissions. Kyoto emerged from the UN Framework Convention on Climate Change (UNFCCC), which was signed by nearly all countries at the 1992 meeting popularly known as the Earth Summit. This was a key milestone in ROCKWOOL’s history, creating awareness of how insulation can contribute to significant reductions in CO2 emissions. It also initiated a debate in the EU about how to reduce energy consumption and energy dependency. This resulted in an EU paper presented in 2000, which for the first time documented that 40.3 percent of total energy consumption in the bloc comes from buildings.

RockWorld imagery, products with life, factory, industrial, work, construction


Strategic focus on technology and R&D leadership

In 1992, a HQ Group Technology function was established, responsible for global coordination of production, environment, investments, logistics, R&D, norms and standards, patents, and engineering – everything to do with the design and construction of manufacturing equipment, production lines and plants. This solidified the foundation for ROCKWOOL’s strong global leadership in stone wool.

RockWorld imagery, The big picture, buildings, greenery, park, trees, city


The ROCKWOOL Group becomes a listed company

In 1996, ROCKWOOL International was listed on the stock exchange at Nasdaq Copenhagen. The Company’s shares were listed in two classes – ROCKWOOL A and ROCKWOOL B. Each A share carries 10 votes, while each B share carries one vote. The ROCKWOOL Foundation today owns 23 percent of the ROCKWOOL Group, making it the largest shareholder.

Sydhavn Skole, Durability


Expansion eastward and beyond

In 1999, the Russian factory near Moscow was acquired; the same year in which the Canadian factory in Grand Forks and the Italian factory in Sardinia (which was later closed) were acquired. Prior to the expansion in Russia the factory in Eastern Germany was acquired in 1991. In 1993 and 1995 two factories in Poland were acquired, in Cigacice and Malkinia; a factory in Goganfa, Hungary was acquired in 1997; and in the Czech Republic, a factory in Bohumin was purchased in 1998. Rockfon production started in 1992 in Saint-Éloy-les-Mines, France, and in 1997, Rockdelta was established, offering solutions for vibration and noise control.



The ROCKWOOL Foundation

The ROCKWOOL Foundation was established in 1981 by Claus Kähler and his five siblings. Each donated shares from their own holdings to ensure that the Foundation – at that time owning 25 percent of all shares – would be a major shareholder and have a major say in the future development of the ROCKWOOL Group. The Foundation is an independent and financially self-supporting organisation, which aims to generate knowledge that can help tackle problems facing society today. It achieves this through impartial scientific research into social and economic issues, and by carrying out practical interventions. The Foundation’s work is particularly focused on issues related to the sustainability of the welfare society. Research is conducted by both the ROCKWOOL Foundation’s Research Unit and specialist external researchers, while practical interventions are managed by the Foundation’s Interventions Unit.

TBS (In translation)


New generation of stone wool fibres

In 1982, fibres with even higher temperature stability were created, forming the basis for today’s high-temperature, bio-soluble stone wool. The new development used the high-temperature properties of the Spinrock fibre developed in the 1970s to set new standards in the market.

TBS (In translation)


Expansion through Europe and North America

In 1980, ROCKWOOL Isolation S.A. was established with a sales office in Paris and a factory in Saint-Éloy-les-Mines, and in 1985 the factory in Hiltrup, Germany was acquired, and the sales office in Austria was established. Offices were set up in Italy and in Spain in 1989. In 1988, ROXUL Inc. was established in Toronto, Canada. In the following years, four additional factories were built in the US and in Canada, and ROCKWOOL’s position grew significantly. With five factories and 1,000 employees, ROXUL has become North America’s largest stone wool producer, offering advanced building insulation, industrial and technical solutions.

TBS (In translation)


Always innovating

Constantly optimising the ROCKWOOL mineral fibre technology and pursuing new ideas have always been key priorities for the Group R&D organisation. In the 1970s, this led to the development of a fibre that could replace asbestos to reinforce materials and products such as bitumen, paints, adhesives and brackets. Launched in 1974, Spinrock Fibres were a radical innovation for the 1970s, demonstrating how looking for healthier, more sustainable and environmentally friendly products has always been part of ROCKWOOL’s DNA.

TBS (In translation)


ROCKWOOL International A/S founded

In 1976, ROCKWOOL International A/S was set up as a holding company for the entire Group, during a decade that saw the business develop and expand significantly. In 1970, 50 percent of the shares of the Nederlandse Steewolfabrik in Roermond in the Netherlands were acquired, with the remaining 50 percent purchased in 1975. Also that year, 50 percent of the shares in ROCKWOOL AB are sold to the Swedish State, which already owned the other 50 percent. In 1977, the factory in Doense began operations and in 1978 the subsidiaries Grodania and Rockfon were set up. The end of the decade, 1979, saw the establishment of ROCKWOOL Limited in Bridgend, UK.

The packing areas of the factory in Hedehusene late 1970.


Circular thinking

The development in the early 1970s of Spinrock fibres, which helped industries to replace asbestos,
led to ROCKWOOL’s recycling concept. Plant workers in Hedehusene found that old stone wool products could be recycled if they were ground and mixed into briquettes. The first briquettes were made in 1978 for Spinrock and in 1979, this process was tested and implemented in the plant in Hedehusene, creating the foundation for a comprehensive “circularity” concept. The recycling of ROCKWOOL Group’s own production waste was extended further in subsequent years, to cover recycling schemes for external construction waste and demolition waste.

Claus Kähler later to be CEO for 24 years, was employed in 1948.


The Kähler family takes sole responsibility for the ROCKWOOL business

In 1962, the Kähler and Henriksen families agreed to split and establish two new companies. Jens Nørgaard, later to become CFO of the ROCKWOOL Group, proposed a new company structure with the ROCKWOOL activities in one group and all others – sand pits, the aerated concrete business and Hasle tiles – in another group. The Henriksen family then chose the group they preferred and the company’s activities were split accordingly. On 1 January 1962, the name was changed to I/S Kähler & Co., with the Kähler family taking sole responsibility for the ROCKWOOL business.

TBS (In translation)


First use of spinning technology

In 1952, ROCKWOOL acquired the licence from Johns Manville in the USA to use spinners for drawing fibres. The new process used diabase rock instead of slag, creating fewer shots (small pieces of stone that have not been spun into fibres), lower densities and more robust fibres. The result was wool with a significantly higher and more homogeneous quality. In 1953, the 4-wheel spinner was introduced, dramatically increasing potential output, which has grown from 0.6 tonnes per hour in the early 1950s to over 20 tonnes per hour today. The year 1954 was a turning point, as production with added binder worked smoothly and the quantity of slabs produced overtook sewn mat products. Mat products however continued to be an important part of the product portfolio and in 1959, ROCKWOOL acquired a patent covering lamella mats for pipe insulation.

ROCKWOOL Laboratory management 1963


ROCKWOOL engineering department founded

Deep knowledge of core technologies has always been key to ROCKWOOL’s success. To build on this, the company set up its own engineering department in Hedehusene, with five employees.

TBS (In translation)


Geographical expansion

In 1954, ROCKWOOL established its first non-Scandinavian subsidiary in Germany. In 1958, the headquarters moved from Korsør to Hedehusene and expansion continued in 1959 with the opening of a second factory in Trondheim, Norway.

Factory workers 1940


Binder expands stone wool’s potential

ROCKWOOL acquired the licence from Baldwin Hill to add binder to the stone wool, making it possible to develop products with good dimensional stability. This change significantly expanded the ROCKWOOL product portfolio, creating a foundation for today’s diverse product range.

Production at the Factory in Hedehusene late 1930.


Stone wool production licenced

I/S Henriksen and Kähler acquired the licence to produce stone wool in Denmark, Norway, Sweden and Germany from New Jersey, USA-based Baldwin-Hill. The production process, based at the time on steam-blown fibres, was used to make loose wool and sewn mat products. It was a further 17 years before the more efficient and versatile spun wool production process was introduced.

The wool chamber in the late 1930s.


Stone wool production in Denmark

The stone wool plant in Hedehusene, Denmark, began production. It burned down in 1938 but was rebuilt the same year. Also that same year, production of ROCKWOOL mineral wool began in Skövde in Sweden and Larvik in Norway. By 1939, total production had risen to 2,000 tonnes per year in Hedehusene alone.