100mm Rockwool EWI External Wall DD Slab

100mm Rockwool EWI External Wall DD Insulation Slab delivers superior thermal performance for wall insulation applications, engineered to work seamlessly with accredited External Wall Insulation (EWI) systems.

Manufactured using Rockwool's innovative Dual Density technology, these slabs feature a robust high-density outer layer paired with a flexible lower-density core. This construction delivers an exceptionally strong surface for rendering and fixture installation, whilst the softer underside accommodates substrate imperfections effortlessly.

When installed with tight joints, the slabs interlock to create a continuous thermal barrier, eliminating heat loss through gaps and cracks. Specifying 100mm Rockwool DD insulation provides lasting confidence in your building's insulation performance. Stone wool insulation delivers proven durability, with performance verified over 55+ years of real-world use.

Product specification

• Brand: Rockwool®
• Model: 100mm EWI
• Thickness: 100mm
• Dimensions: 1,200mm x 600mm x 100mm
• Length: 1200mm
• Width: 600mm
• Board Coverage: 0.72m2
• Colour: Pale white
• Density: 110kg/m3
• Compressive strength: ≥ 10 kPa
• Tensile strength: ≥ 10 kPa
• R-Value: 1.39m2K/W
• Thermal Conductivity: 0.036W/mK
• Material: Molten volcanic rocks
• Profile: Square edge
• Temperature resistance: up to 1000ºC
• Fire Classification: A1 Non-combustible
• Shipping method: Articulated Vehicle ǀ Courier
• Applications: External Wall Insulation Systems
• Features: Thermal and Acoustic Insulation Slab
• Manufacturer: ROCKWOOL®

The 100mm Rockwool External Wall Dual Density Slab combines precision engineering with proven performance for external wall applications. These 100mm external wall insulation boards incorporate dual-layer construction with contrasting densities: a softer base layer that tolerates building fabric variations, and a firmer top layer ideal for render application. Installation requires both mechanical fixings and quality adhesive to secure boards firmly to the substrate, with a minimum of 7 fixings per square metre recommended.

Application

Install 100mm Rockwool Mineral Wool insulation slabs according to manufacturer guidance, which outlines design specifications and installation procedures. For optimal adhesion, fix boards using mortar or adhesive combined with mechanical fixings.

Given mineral wool's substantial weight, the EWI-225 Premium Basecoat is preferable to standard adhesives suited for lighter materials. Apply a thin, diluted adhesive coat to the prepared substrate first. After drying, apply the basecoat and embed the Fibreglass Mesh.

Non-combustible

100mm Rockwool stone wool achieves the highest 'A1 – Non-combustible' rating under the European Reaction to Fire Classification System, guaranteeing it will not ignite or fuel fire spread.

Durable

1. 100mm Rockwool DD slabs preserve dimensional stability throughout a building's lifespan, resisting shrinkage and material degradation.
2. The dense outer surface enables secure basecoat bonding and prevents fastener over-driving.
3. Delivers excellent resistance to wind and rain exposure during construction phases.
4. Proven track record: 100mm Rockwool has performed reliably in European EWI systems for over 40 years.

Breathable

• 100mm Rockwool stone wool features an open-cell breathable structure that permits water vapour transmission, whilst water-resistant fibres prevent moisture penetration.
• Provides vapour resistance equivalent to still air conditions.

Thermal performance

Closely butted slabs allow fibres to interlock efficiently, preventing thermal losses through gaps and joints in the insulation layer.

Acoustic performance

• Buildings with 100mm Rockwool slabs in EWI systems benefit from enhanced envelope mass, which dampens sound and vibration transmission.
• The fibrous material contributes to sound dampening, with test data showing weighted sound reduction improvements of up to 8 dB, Rw (varies by substrate).

Dual Density Slabs for External Walls

• Engineered specifically for external wall insulation applications, Dual Density Slabs provide a premium stone wool insulation option.
• Manufactured using ROCKWOOL's proprietary 'dual density' process, these slabs incorporate a denser top layer than the remainder of the product. This delivers a reliable surface for rendering and fixture mounting, whilst the compliant underside conforms to substrate variations.
• The top layer is clearly marked 'THIS SIDE UP' for straightforward installation and correct orientation.

More Information on 100mm Rockwool External Wall DD Slab

• Manufacturer Link: Rockwool DD
• 100mm Rockwool External Wall DD Slab represents high-performance insulation with broad application possibilities.
• Explore our full Rockwool Insulation range and refine by thickness or coverage using the filters on the left. For project-specific advice or bulk pricing enquiries, contact us on +4402038839057, email sales@insulationbee, or use Live Chat - Competitive UK Rockwool Insulation Pricing.