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Rockwool Flexi Insulation Slab - 40kg/m3

Original price £49.84 - Original price £52.00
Original price
£49.84
£49.84 - £52.00
Current price £49.84

Order by Wednesday 18th December to guarantee delivery before Christmas. We will close for Christmas on Monday 23rd and will reopen on Thursday 2nd Jan.
🛠️ Minimum Order Value

This product is from our Building Materials range, which have a minimum order value of £140. View our Building Materials range to browse all the qualifying products.


  • 40kg density mineral wool slabs

  • Ensures the insulation integrity

  • 1200mm x 600mm slabs are ideal for work between stud work or battens

Can potentially provide over 30dB of protection depending on quality of door, and surrounding sound insulation.

The Rockwool Flexi Insulation Slab is a versatile and multi-purpose thermal and acoustic insulation solution crafted from volcanic rock. With a density of 40kg/m³ and a unique patented flexible edge, it ensures a snug fit between timber or metal frameworks. This semi-rigid insulation offers excellent soundproofing and thermal performance, making it ideal for residential, commercial, and industrial applications. Rated Euroclass A1 non-combustible, it combines fire safety with superior acoustic and thermal insulation properties.

What is a Rockwool Flexi Insulation Slab?

The Rockwool Flexi Insulation Slab is a high-performance insulation material specifically designed to provide thermal, acoustic, and fire resistance. Its unique flexible edge ensures a perfect fit, reducing the risk of gaps caused by timber contraction or irregular framing. The slabs are made from 97% recyclable volcanic rock, making them an eco-friendly and sustainable choice for insulation projects.

Specifications:

  • Density: 40kg/m³
  • Dimensions: 1200mm x 600mm
  • Fire Resistance: Euroclass A1 non-combustible
  • Material: Volcanic rock wool with flexible edges

How Does the Rockwool Flexi Insulation Slab Work?

The Rockwool Flexi Insulation Slab works by leveraging its unique composition and flexible edge to deliver superior thermal, acoustic, and fire protection:

  1. Thermal Performance:
    • The dense mineral wool fibres trap air, reducing heat transfer and maintaining energy efficiency within a building.
  2. Acoustic Performance:
    • The flexible edge creates a friction fit, eliminating gaps and preventing sound leakage. This reduces airborne noise and improves sound absorption.
  3. Fire Resistance:
    • The slab is non-combustible, withstanding extreme temperatures and helping to compartmentalise spaces to limit fire spread.
  4. Moisture Resistance:
    • The non-hygroscopic material repels water, preventing dampness, rot, and mould growth.

How Effective are the Rockwool Flexi Insulation Slabs at Stopping Nuisance Noise?

The Rockwool Flexi Insulation Slabs are highly effective at reducing noise transmission:

  • Airborne Noise Reduction:
    • The mineral wool slabs absorb sound waves, providing noise reduction of over 30dB when used with appropriate surrounding materials.
  • Sound Absorption:
    • The tight fit achieved by the flexible edge ensures no gaps, maintaining the slab’s full acoustic performance.
  • Reverberation Control:
    • Minimises reverberant noise within enclosed spaces, improving overall acoustic quality.

Where Can the Rockwool Flexi Insulation Slab Be Used?

The Rockwool Flexi Slab is versatile and suitable for various applications, including:

  • Residential Projects:
    • Internal partitions, separating walls, and floors
    • Timber suspended ground floors
    • Pitched roof rafters
  • Commercial and Industrial Projects:
    • Acoustic ceilings, framed walls, and partition panels
    • Fire-rated construction projects
  • Specialist Uses:
    • Ideal for spaces requiring noise reduction and thermal efficiency, such as home theatres, studios, and offices.

How to Install the Rockwool Flexi Insulation Slab

Installing the Rockwool Flexi Insulation Slab is straightforward, thanks to its flexible edge:

  1. Preparation:
    • Measure the space between studs or battens and cut the slab to size if necessary.
  2. Placement:
    • Insert the slab into the void. The flexible edge ensures a friction fit, preventing gaps or cold spots.
  3. Securing:
    • No additional fixings are required for friction-fit installations. For ceilings or complex configurations, additional support may be used.
  4. Finishing:
    • Cover the insulation with plasterboard, timber panels, or other finishing materials as required.

What are the Benefits of Using the Rockwool Flexi Insulation Slab?

  1. Superior Acoustic Insulation:
    • Reduces airborne noise by over 30dB, creating quieter and more comfortable spaces.
  2. Thermal Efficiency:
    • Helps regulate indoor temperatures, reducing energy consumption and costs.
  3. Fire Safety:
    • Rated Euroclass A1 non-combustible, providing the highest level of fire resistance.
  4. Moisture Resistance:
    • Repels water, preventing damp, rot, and mould growth.
  5. Sustainability:
    • Made from 97% recyclable volcanic rock, with no ozone-depleting or global warming potential.
  6. Durable and Long-Lasting:
    • Retains its performance throughout the lifespan of the building.
  7. Versatile Applications:
    • Suitable for walls, floors, ceilings, and roofs in residential, commercial, and industrial settings.
  8. Easy Installation:
    • The patented flexible edge ensures a perfect fit, eliminating the need for complex fixings.

The Rockwool Flexi Insulation Slab is an innovative and reliable solution for thermal, acoustic, and fire protection needs. Its ease of installation, sustainability, and superior performance make it an essential choice for modern construction and soundproofing projects.

Here are the main details for this product:

Dimensions:

1200mm x 600mm

Thickness: 50mm / 70mm / 100mm Options

Pack Size:

50mm - Pack of 12
70mm - Pack of 8
100mm - Pack of 6

Weight: TBC

Density: 40Kg

Coverage: sqm

Fire rating: Fire Properties Euroclass A1

Thermal Conductivity:

View Product Information Guide

Please contact our team if you have any questions on this product.

Looking for a complete soundproofing solution?

If your looking for soundproofing for a particular situation or application, then the best place to start is with our soundproofing solutions that cover walls, floors, ceilings and reducing echo. Select the relevant application below to find out more.

Wall Solutions

Floor Solutions

Ceiling Solutions

Echo Solutions


Visit our Fitting Instructions section for more detailed instructions relating to your specific application.

Check out our Soundproofing Guides for more information, advice and tips on all aspects of soundproofing.