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Rockwool External Wall Insulation High Density Slab

Brand: Rockwool
£45.13 Incl. VAT
£45.13 Incl. VAT (regular price)
Please note: This product has a slightly longer lead time. Our team wiil notify you with an estimated delivery date.

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    Rockwool External Wall Insulation High Density Slab is a robust stone wool insulation solution, purpose-built for use in external wall insulation (EWI) systems where enhanced mechanical performance is essential. Engineered for areas that demand higher tensile strength, this high density slab offers exceptional durability and thermal performance.

    With a Euroclass A1 fire rating in accordance with BS EN 13501-1, the slab is non-combustible, making it ideal for applications requiring the highest level of fire safety. The slab delivers thermal conductivity values of 0.038 W/mK (30–40mm) and 0.039 W/mK (>40mm), helping improve the energy efficiency of the building envelope. It also boasts excellent mechanical properties with ≥15 kPa tensile strength perpendicular to the face and ≥10 kPa compressive strength, ensuring reliable performance in demanding conditions.

    Applications

    Perfect for use in EWI systems across various building types, especially where increased impact resistance and structural integrity are required.

    Thicknesses and Coverage Rates

    30mm (Pack of 5 Slabs) 3.66 (m²)
    40mm (Pack of 64 Slabs) 46.08 (m²)

    Technical Data

    Product Type Stone Wool (Rock Mineral Wool)
    Application External Wall Insulation Systems
    Thermal Conductivity (λ) 0.038 W/mK (30–40mm), 0.039 W/mK (>40mm)
    R-Value 30mm: 0.79 m²K/W, 40mm: 1.05 m²K/W
    Fire Classification Euroclass A1 (EN 13501-1) – Non-combustible
    Tensile Strength ≥ 15 kPa
    Compressive Strength ≥ 10 kPa
    Water Vapour Resistance (μ) Typically < 1 (highly breathable)
    Moisture Resistance Water repellent
    Density Approx. 120–150 kg/m³
    Slab Dimensions 1200mm x 600mm
    Thickness Range 30mm – 40mm
    Weight Approx. 2.2–3.6 kg per slab (based on 50mm)
    Facing No Facing
    Product Standard EN 13162:2012+A1:2015
    Declaration of Performance (DoP) UK-WER-0130
    CE Certificate Number 0751-CPR-393.0-01
    Compatibility Suitable with EWI systems using mechanical fixings and render finishes

    Frequently asked questions

    Dual density slabs feature two layers with different compressive strengths: a denser outer layer for impact resistance and a softer inner layer for easier fixing and improved conformity to uneven surfaces. In contrast, high density slabs have a uniform density throughout, offering consistent rigidity but less flexibility during installation. Dual density provides an optimal balance of durability and workability, particularly ideal for external wall insulation systems.

    The Rockwool High Density Slab is classified as Euroclass A1 in accordance with BS EN 13501-1, meaning it is completely non-combustible and provides the highest level of fire resistance.

    The slab provides excellent thermal insulation with a thermal conductivity of 0.038 W/mK for thicknesses between 30–40mm, and 0.039 W/mK for thicknesses over 40mm, helping to reduce energy loss through external walls.

    Yes, thanks to its high mechanical strength and non-combustible properties, the High Density Slab is well-suited for use in high-rise and multi-storey buildings, where enhanced safety and performance are critical.

    While it delivers excellent performance, it is designed to be used as part of a complete external wall insulation (EWI) system. Pairing it with suitable fixings, basecoats, and finishes ensures long-term durability and compliance with building regulations.