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 RW3 slab is sized with installation in mind. The dimensions allow a snug friction fit between studs, joists, or rafters, meaning no additional fixings are typically needed. Its semi-rigid form makes trimming and shaping straightforward, even in more detailed or irregular areas.

RW3 is used in a range of internal applications, including partitions, separating walls, intermediate floors, ceilings, and service zones (where both thermal and acoustic control are priorities).

The material repels water while still allowing moisture vapour to pass through. This helps reduce the risk of condensation and supports a healthier internal environment over the long term, both for the building and the people using it.

Applications

• Partition Walls: RW3 slabs are well-suited to internal walls where both heat retention and noise reduction are required. They help regulate room-to-room temperature while limiting the transfer of sound through studwork.
• Ceilings and Roofs: With a Euroclass A1 fire rating, RW3 adds an extra layer of protection in overhead spaces, slowing the spread of fire in roof or ceiling builds.
• Floors: Installed between floor levels, RW3 muffles airborne noise and acts as a thermal blanket, helping rooms retain their heat.
• Commercial and Industrial Settings: The slab’s stone-wool core copes well with hard-working environments such as factory bays, warehouse offices, and plant enclosures. Because it won’t burn, it strengthens a site’s fire strategy, and its dense fibres take the edge off constant machinery noise.

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.
• Fire Safety: RW3 carries a Euroclass A1 rating (the highest level of non-combustibility under EN 13501-1). The stone-wool fibres char and lock together in fire, forming a barrier that slows flame spread, limits smoke and buys vital time for evacuation or first-response work.
• Acoustic Control: A dense mineral-wool core soaks up airborne noise, reducing sound transfer through partitions, intermediate floors and service ceilings. The result is quieter flats, offices and plant rooms without the need for extra acoustic boards or resilient bars.
• Moisture Behaviour: Liquid water beads on the fibre surface rather than soaking in, yet the slab still lets vapour pass through. That balance helps keep cavities dry and discourages mould, rot and vermin, extending the service life of the insulation in humid zones such as basements or coastal locations.
• Sustainability: RW3 is made from naturally occurring rock and contains recycled content. It is fully recyclable at the end of its life, and its long lifespan means fewer replacements and less waste over the building’s lifetime.

Certifications

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