Rockwool RW3 Slab

What is Rockwool RW3?

Rockwool RW3 is a versatile, high-density (60 kg/m³) mineral-wool slab that reliably satisfies stringent thermal, acoustic, and fire-resistance standards, all in a single, performance-driven solution.

Developed as part of the Rockwool RW range, RW3 stands out for its ability to perform in high-stress environments, combining exceptional heat retention, sound dampening, and Euroclass A1 non-combustibility in a single solution.

Each 1200mm × 600mm slab is dimensioned for efficiency on-site, offering a secure friction-fit between studs, joists, and rafters without the need for fixings. Its semi-rigid structure is easy to cut and shape, allowing quick adaptation to complex layouts. 

Whether it's used in internal partitions, separating walls, intermediate floors, ceilings, or service voids, RW3 ensures a quieter, safer, and more energy-efficient environment. 

Resistant to water absorption yet vapour-permeable, it also helps prevent condensation and mould, supporting the long-term health of both buildings and their occupants.

Applications

• Partition Walls: RW3 slabs marry thermal and acoustic insulation, minimising sound transmission and contributing to temperature control between rooms. 
• Ceilings & Roofs: RW3’s Euroclass A1 fire rating adds a vital layer of protection overhead, helping contain flames and slow their spread in critical roof and ceiling assemblies.
• Floors: The slab’s dense fibre matrix blocks airborne noise between storeys while its low thermal conductivity cuts heat loss - boosting acoustic comfort and energy efficiency in multi-level homes and offices.
• Commercial & Industrial Areas: Non-combustible, rigid, and durable, RW3 is ideal for factories, warehouses, and plant rooms, where it reinforces fire-safety strategies and dampens operational noise under demanding conditions.

Rockwool Insulation RW3 Insulation Slabs Benefits

Thermal Insulation 

• Offers effective thermal insulation with a low thermal conductivity of just 0.034 W/mK. 
• Reduces dependence on heating and cooling systems, supporting long-term energy savings and regulatory compliance. 

Fire Performance and Resistance

• Holds a Euroclass A1 non-combustible rating - the highest fire-safety classification available. 
• Stone-wool fibres form an effective fire-insulation barrier that compartmentalises spaces, slows flame spread, and buys valuable time for safe evacuation and firefighting.

High-Performance Acoustic Insulation

• Dense mineral wool composition of Rockwool RW3 slabs delivers excellent acoustic insulation. Absorbs sound and reduces airborne noise transmission through walls, floors, and ceilings.
• Particularly valuable in multi-unit residential buildings, office spaces, and industrial settings where noise control is a priority.

Water Repellent and Durable

• Repels liquid water, stopping moisture from seeping in and degrading thermal performance. 
• Built-in water resistance extends the life of the insulation in damp or humidity-prone areas. 
• Because the material is inorganic, it won’t rot, sustain mould, or attract vermin, ensuring durable protection and reducing the need for costly replacements or maintenance.

Sustainable and Environmentally Friendly

• Composed of mineral wool, an environmentally sustainable material that is recyclable and contributes to eco-conscious building practices. 
• Durability and vermin-resistant properties reduce replacement frequency, adding to its environmental benefits. 
• Rockwool’s production processes also align with sustainability goals, making RW3 slabs a responsible choice for green building initiatives.

Benefits

• Dimensions: Each slab measures 1200mm x 600mm, facilitating compatibility with standard building configurations.
• Density: With a density of 60 kg/m³, RW3 slabs achieve optimal balance between insulation performance and structural integrity.
• Thermal Conductivity: A low thermal conductivity of 0.034 W/mK delivers effective thermal regulation, contributing to significant energy savings.
• Fire Rating: Euroclass A1 non-combustible, ensuring the highest available fire safety rating for materials used in building construction.
• Water Repellent: The slabs resist water ingress, preserving insulation efficiency over time and maintaining structural resilience in humid environments.
• Acoustic Properties: The high-density mineral wool composition significantly reduces airborne sound transmission, enhancing acoustic comfort.
• Non-Combustible Material: Made from mineral wool, Rockwool RW3 slabs provide inherent fire resistance, suitable for high-safety applications.
• Eco-Friendly Composition: RW3 slabs are sustainable, recyclable, and support long-term environmental goals in the building industry.

Certifications

BS EN is British and European Standard Specifications. With over 100 years of experience, the British Standards Institute is recognised as the UK’s National standards body. BS EN considers Rockwool RW3 both:

• Euroclass A1 non-combustible in accordance with BS EN 13501-1 - achieving the highest possible level of fire performance
• CE and Key marked in accordance with BS EN 13162:2012 + A1:2015.v
  
  

Rockwool RW3 slabs are also certified by Lloyd's register of shipping as non-combustible materials for use on:

• Fixed offshore installations
• MED classed ships- DTLR MCA approval
• Rated non-combustible in accordance with ISO 1182 and IMO A. 799