Stone wool

Stone wool

Stone wool insulation

Insulation made from stone wool material is considered as a traditional standard.

Stone wool: everything you need to know

Effective insulation is essential in any kind of building and technical application to ensure maximum comfort and lower costs. Developed, used and improved by ISOVER for many years, stone wool insulation products combine mechanical resistance with excellent thermal performance, fire safety and high temperature suitability.

What is stone wool?

Also known as rock wool, stone wool is created by spinning a molten stream of rock, steel furnace slag and recycled materials. Made principally from volcanic rock, it is comprised of 70% natural raw materials including basalt, dolomite and similar rocks, which are generally melted in a cupola furnace with a carbon-containing energy source using optimal energy and environmental protection recovery systems. 


Why choose stone wool insulation?

ISOVER stone wool products combine many advantages in one solution including high levels of mechanical resistance, moisture resistance, excellent thermal and acoustic insulation performance, and superior passive fire protection.  


All our stone wool products come in a range of thicknesses specially tailored for individual applications

  • Efficient fire protection
    Stone wool (or rock wool) provides excellent passive fire protection: it is an incombustible material with the capacity to resist temperature exceeding 1000 °C without fuelling the fire or spreading flames. 

  • Excellent sound absorption
    Non-combustible and lightweight, stone wool has excellent acoustical dampening properties. Stone wool is especially useful when superior fire resistance and acoustical performance are required.

  • High levels of thermal insulation
    The tiny pockets of air trapped within the physical structure of the stone wool reduce airflow and heat flow. Stone wool maintains its shape and density over time for long-term thermal performance throughout the lifetime of the building or technical application.

  • Environmentally friendly
    We constantly seek to reduce our resource use and emissions emitted during the production process and supply chain. Stone wool is made of up to 50% recycled content and has a positive energy and CO2 balance after 3 months. 

What can stone wool be used for?

Stone wool (rock wool) can be used for insulation and fire protection in many applications. It is particularly suitable for industry given its high temperature resistance and non-combustibility. 

Some of our most popular stone wool products :

  • TECH Loose Wool HT
    Loose stone mineral wool for high-temperature industry applications
  • TECH Slab MT
    Premium performance rigid stone mineral wool slabs
  • TECH Wired Mat MT
    Enhanced thermal and acoustic performance for industrial applications, alongside top-level fire classification

Focus on ULTIMATE™


ULTIMATE™ is an innovative new mineral wool from ISOVER that combines the performance benefits of glass wool and stone wool. The challenge for our R&D team? Creating a product capable of operating at much higher temperatures than traditional glass-wool products.

With a patented composition and unique fiberizing method, we are able to produce a 100% converted fibre structure that offers superior sound, thermal and fire protection properties. 

Find out more

How do we make stone wool?

Stone wool, also referred to as rock wool, is created by spinning molten rock and minerals with steel slag to create a cotton-candy-like wool product. 


1. Composition: The basalt, slag and briquet (recycled stone wool) are stored in silos. These raw materials are then automatically weighed and mixed with coke.
2. Fusion: This mixture is fused through coke combustion in a cupola heated to over 1,500 °C.
3. Fibre drawing / Binder: The fibre is drawn by projecting glass on high-speed rotors. A binder is automatically atomized on the fibres and the fibre core is placed in a pressurized chamber to form a homogenous primary sheet. This blanket is then transported to the batting installation.
4. Batting creeping: 
The arm stacks the stone wool zigzagging perpendicularly on a mat underneath. Batting increases the number of layers to achieve a wider range of basis weights. Using a roller system, the multi-layer wool blanket can be directed and compressed. Crimping straightens the fibres to improve their mechanical characteristics.
5. Polymerisation: 
The binder-impregnated products are transported to an oven heated to over 200°C. The hot air that passes through the stone wool blanket polymerises the resin, which gives the blanket its final thickness and consistency. 
6. Packaging / Palletization: Once out of the oven, the blanket is cut to the required width. Any edge waste is recycled during the manufacturing process. The stone wool blanket can be covered with a paper or aluminium covering, or a glass or asphalt mat.

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