Rockwool was founded as Korsør Stenforretning by constructor Henrik Johan Henriksen and brickyard-owner Valdemar Kähler in 1909 as a gravel mining company. In 1922, the company won the contract on improving the dykes at Saltbæk Vig and later purchased the area.In 1927, it purchased a chipping plant at Hedehusene. In 1937, a production of mineral wool was established at the site based on an American license acquired by Finn Henriksen during a visit to the States. By 1939, the focus of the company had fully turned toward the manufacture of insulation.In 1972, the company was divided into H+H and I/S Kähler & Co. Kähler & Co. was led by Valdemar Kähler's grand son Claus Kähler. He was succeeded on the post by his son Tom Kähler in 1986. In 2004, Tom became chairman of the board while Eelco van Heel took over the position as chief executive officer.
The company began trading as "Rockwool International A/S" on the Copenhagen Stock Exchange in 1995. Before it became a public company, it was a family-owned business, held by the Kähler family.
The company's first plant in the United States opened in 2014 in Marshall County, Mississippi. In 2017, the company announced a North American expansion through establishment of a plant in Ranson, West Virginia through its subsidiary Roxul.
