Owens Corning is going into the mineral wool insulation business.

The Toledo, Ohio, company has purchased Thermafiber Inc., a manufacturer of mineral wool insulation for residential, commercial, and industrial markets.

Owens Corning already makes a variety of insulation products, including its familiar pink fiberglass batts, blown-in fiberglass, extruded polystyrene, and duct liner and duct board.

Thermafiber has a single 145,000-sq. ft. plant in Wabash, Indiana, with about 150 employees. Owens Corning would not say how much insulation the plant currently produces.

Thermafiber makes its mineral wool insulation from rock and blast furnace slag. It’s non-combustible, inorganic, and mold-resistant and has an R-value of about R-4 per inch, Thermafiber says. It is sold as loose fibers or formed into blankets or boards.

Owens Corning said the purchase did not signal it was preparing to get out of the fiberglass insulation business. Mineral wood currently has a 4% share of the U.S. insulation market.

Joe Ochoa, vice president and general manager, for Owens Corning Engineered Insulation Systems, said in a prepared statement: “Mineral wool insulation adds to our product portfolio and helps us to provide access to high-temperature commercial building applications.” The company said its short-term focus would be to take care of existing customers while it developed a long-term growth plan.

Terms of the sale were not disclosed.