rockwool

Rockwool is a class of mineral wool insulation materials produced by melting natural rocks such as basalt and other minerals, then forming the molten material into fibers. These fibers are spun and gathered into products that come as batts, boards, slabs, pipes, and loose-fill for various insulation and soundproofing applications. Rockwool products are marketed for use in building envelopes, HVAC systems, industrial insulation, and, in horticulture, as a growing medium.

Production and composition

Rockwool is made by heating basalt rock and other feedstocks to high temperatures until they melt, then extruding or spinning the melt into fibers. The fibers are typically bound with binder resins to form rigid or semi-rigid products. Some products are faced or laminated for handling, installation, or moisture control. The resulting material is lightweight, highly porous, and designed to resist heat transfer and flame.

Properties

Rockwool is non-combustible and generally classified as a high fire-resistance insulation material. It provides good thermal insulation and acoustic damping while remaining dimensionally stable over a wide temperature range. The open fiber structure allows vapor diffusion, helping to manage moisture in building assemblies. Densities and thermal conductivities vary by product type, with lower-density batts and boards designed for walls and roofs, and higher-density forms used for industrial piping and machinery insulation.

Uses and considerations

In construction, rockwool is used in wall and roof cavities, under floors, around ducts, and for acoustic barriers. It is also used as a growing medium in horticulture. Health and safety considerations during installation include appropriate protective equipment to minimize fiber irritation; once installed, the material is generally stable and inert.

Environmental notes

Manufacturing is energy-intensive, and some products incorporate recycled content. Rockwool can often be recycled or repurposed at end of life where facilities exist.