What is Mineral Wool Insulation?

What is Mineral Wool Insulation?

Mineral wool insulation, also known as rock wool or stone wool, is made from natural rock and recycled steel slag that is melted and spun into fibers. This creates a dense, fire-resistant insulation material that excels in thermal performance, fire protection, and sound dampening.

Key Benefits of Mineral Wool

• Fire Resistance: Withstands temperatures up to 2000°F without melting
• Sound Dampening: Excellent acoustic insulation properties
• Moisture Resistant: Doesn't absorb water or promote mold growth
• Dimensional Stability: Won't settle, sag, or compress over time

Types of Mineral Wool

Batts and Boards

Semi-rigid boards and flexible batts that fit between framing members. Available in various thicknesses and densities for different applications.

Loose-Fill

Blown-in mineral wool that can be installed in attics and hard-to-reach areas, providing excellent coverage around obstacles.

Performance Characteristics

Installation Methods

Mineral wool can be installed using several methods:

• Friction Fit: Batts are cut slightly oversized and friction-fit between studs
• Mechanical Fastening: Boards can be mechanically attached to surfaces
• Blown Installation: Loose-fill material blown into cavities

Best Applications

Mineral wool excels in applications where fire resistance and sound control are priorities:

• Exterior walls in fire-prone areas
• Party walls between units for sound isolation
• Basement walls and foundations
• Attics and roof assemblies
• Commercial and industrial buildings

Considerations

While mineral wool offers excellent performance, it is typically more expensive than fiberglass. The material can be irritating to skin and requires proper protective equipment during installation. However, its superior fire resistance and acoustic properties often justify the additional cost in appropriate applications.