Rockwool RW3 Slab

(6 Products)

Why settle for standard insulation when you can reap three insulant benefits from one solid solution? Rockwool RW3 slab is an acoustic, thermal and fire insulation suitable for an array of general building applications - from ceilings to walls and floors. This dynamic insulation comes in the form of high-quality resin-bonded slabs and boasts a fire rating of Euroclass A1 non-combustible as well as a non-hygroscopic nature which prevents moisture ingress, damp and rot.

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What Are Rockwool RW3 Slabs?

Rockwool RW3 Slabs are high-performance insulation products made from dense stone wool, specifically designed to provide superior thermal and acoustic insulation in various construction settings. 

Manufactured by Rockwool, these slabs are crafted from rock, offering exceptional fire resistance and safety due to their natural fire-retardant properties. 

The RW3 designation highlights their specific density and rigidity, making them ideal for applications requiring robust structural integrity, such as in walls, floors, and ceilings. 

Additionally, these slabs are effective in sound absorption, significantly reducing noise transmission and enhancing the acoustic comfort of a space. 

Their moisture-resistant nature further contributes to a healthier indoor environment by preventing dampness and mould growth. 

With a focus on sustainability, Rockwool RW3 slabs incorporate a substantial amount of recycled material, aligning with environmentally conscious construction practices. 

Rockwool RW3 Slab Applications

Multi-use in their function, Rockwool RW3 slabs can be considered for a wide range of general building projects - including ceilings, partition walls, and floors - as well as specialist specifications. 

The slabs can be used as acoustic and thermal insulation in the following construction types:

  • Interior timber or steel partition walls
  • Interior timber frame floors
  • Interior timber frame ceilings
  • Acoustic ceilings and partition panels
  • I-joist interior partitions
  • Party walls

Rockwool RW3 Slab Key Features

  • Excellent thermal, acoustic and fire insulation
  • Rot-resistant - withstands mould and mildew
  • Thermal conductivity of 0.034 W/mK
  • Water-repellent qualities of the insulation prevent moisture build-up, dampness and rot
  • Suitable for a wide range of general building applications - ceilings, walls and floors
  • A1 non-combustible
  • 60kg/m3 density
  • 600mm width to fit between studwork
  • Zero Ozone Depletion Potential (ODP)

Rockwool RW3 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

Frequently Asked Rockwool RW3 Slab Questions

How Does Rockwool RW3 Insulation Reduce Sound Pollution?

Rock is a naturally poor conductor of sound, making RW3 the perfect choice for people who want to insulate their homes against unwanted noise. 

Rockwool respectfully thrashes competitor brands with its prevention of noise transmission from room to room, making it ideal for installation in internal and separating walls. 


Rockwool RW slabs work in two distinct ways to dampen sound, either by impeding the transmission of sound through an element of the structure or by absorption of sound at the surface.

Are Rockwool RW3 Slabs Waterproof? 

Although not entirely waterproof, Rockwool insulation is moisture-resistant and vapour permeable. 

Rockwool does not wick water, meaning water will drain away rather than soak into the insulation, while gaseous water vapour will simply pass through it. Therefore, if Rockwool gets wet, you can dry the material out and it will maintain its original performance characteristics.

Can You Touch Rockwool RW3 Slabs With Bare Hands?

Whilst it won't exactly kill you, the dust from Rockwool can irritate the skin and eyes if the correct PPE is not adorned during handling. 

We always advise wearing the appropriate safety gear when working with Rockwool: gloves, goggles and a mask should be worn at all times. 

If you are to touch the material with bare hands (not recommended), wash your hands thoroughly with cold water after contact. 

How Long Will Rockwool RW3 Slabs Last Before They Have To Be Replaced?

Should you correctly install the insulation (according to manufacturer guidance), Rockwool RW3 slabs should last the lifetime of your structure. Since Rockwool products are inorganic they will not decay and left to it, they should sustain performatively - given that the slabs endure no damage. 

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