Mineral wool is made from natural rock. It is popular in Canada and Europe. It is made from basalt and slag that has been melted in steel mills. The fiber can then be spun into boards or batts. These are the pros and cons: Prices: Fiberglass batts are more expensive than mineral wool batts. R-19 mineral wool is a good example. It costs around 90C/ sq. Fiberglass costs 70C/ per square foot, while R-19 mineral wool is about 90C/ per sq. Fire resistance: The mineral wool resists extreme heat more than any other type of insulation. The batts will retain their form and provide better protection from a flame spread in a fire. Water resistance: Mineral wool insulation, just like fiberglass insulation, does not absorb water. The batts will still look great if the roof or wall leaks. Cellulose, on the other side, absorbs water. To restore the R-value, you will need to have a new installation. Sound Barrier: One the best properties of mineral wool material is its ability to block sound. It is used by many contractors to block sound from the basement or floors.