What is mineral wool insulation?

Mineral wool insulation is a popular and effective type of insulation made from natural or synthetic minerals. It’s used in buildings to keep heat in (or out), reduce noise, and improve fire safety.

What Is It Made Of?

There are two main types:

  1. Rock wool (stone wool) – made from melted volcanic rock (like basalt)

  2. Slag wool – made from recycled steel industry waste (slag)

These materials are melted at super-high temperatures and spun into a fluffy, wool-like texture.

What Forms Does It Come In?

  • Batts or slabs – for walls, floors, and roofs

  • Loose-fill – for attic spaces

  • Rigid boards – for external insulation systems

Benefits of Mineral Wool

  • Great at insulating – keeps homes warm in winter, cool in summer

  • Fire resistant – won’t burn or spread flames

  • Soundproofing – excellent for blocking noise

  • Water repellent but breathable – helps manage moisture

  • Eco-friendly – often made with recycled content

Where’s It Used?

  • Between wall studs

  • In attic floors

  • Around boilers or pipes (high-temp applications)

  • In external wall systems (like ETICS)