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Rockwool RWA45 Acoustic Insulation Slab (4 Products)

When it comes to soundproofing your home, Rockwool Acoustic insulation is simply unrivalled. Rockwool is the UK's leading manufacturer of sustainable, non-combustible stone wool insulation. 
These high-quality acoustic and thermal insulation resin bonded slabs not only do a cracking job of soundproofing, but they also feature phenomenal fire resistance properties - as proven by their outstanding Euroclass A1 non-combustible rating. RWA45 is also water repellent - promising maximum protection for the lifetime of your build.

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Rockwool RWA45 Acoustic Insulation Slab

What Are Rockwool RWA45 Insulation Slabs?

When the day is done and you’re all wrapped up with work, you deserve to come home to a quiet and relaxing space. RWA45 slabs are designed to stop the transfer of sound and heat from one space to another, making them an ideal choice for use in residential buildings such as home offices, studios, bedrooms and anywhere else you want to get the silent treatment. At Materials Market, we stock Rockwool’s most popular insulation slab to date; the RWA45 Acoustic Insulation Slab 1200 x 600.

The fact that RWA45 insulation is made from mineral wool makes it a naturally renewable and sustainable material; so it gets a big green thumbs-up for its environmental credentials. Another perk of the slab's inorganic composition is that it provides it with water repellent qualities which prevent moisture build-up, dampness and rot.

These high-quality acoustic and thermal insulation resin bonded slabs offer excellent thermal, acoustic and fire performance and are also as easy to fit as they are to handle. The 1200mm x 600mm slabs can be cut into shape with a serrated blade. As the texture is quite similar to a loaf of bread, the slabs can actually be cut with a bread knife (given it has a serrated blade) - but for legal reasons, and the taste of your next sandwich, just make sure you give the knife a good wash before using it on actual bread.

These high-quality resin bonded slabs also achieve the highest level of fire performance with an outstanding A1 non-combustible rating in accordance with BS EN 13501-1.

What Are Rockwool RWA45 Acoustic Insulation Slabs Made From?

The production process for Rockwool essentially emulates the inside of a volcano that spins and cools lava in a controlled environment. Rockwool insulation is created by spinning molten rock and minerals with steel slag to create a cotton-candy-like wool product.

What Does RWA45 Mean?

RWA45 is the name that Rockwool gives to their most popular acoustic insulation slab. The RW stands for “Rockwool”, A stands for “Acoustic” and the 45 refers to the fact that these slabs have a density of 45kg/m3 and 0.035 W/mK thermal conductivity. You will see that there is more than one product on our site labelled RWA45. All slabs are essentially the same product, just with varying thicknesses. Our 25mm Rockwool RWA45 acoustic sound insulation slab (16 slabs per pack) is the same as our 100mm Rockwool RWA45 acoustic sound insulation slab (4 slabs per pack), only it is not as thick, and therefore will not provide the same level of soundproofing.

You can read more about these materials on Rockwool RWA45 data sheets, which you can find under ‘Technical Downloads’ on each product page.

Rockwool RWA45 Acoustic Insulation Slab Thickness

The RWA45 product range consists of different thicknesses to suit every kind of project. Our customers can choose slabs in a variety of thicknesses; 25mm (11.52m2 pack), 50mm (6.48m2 pack), 75mm (4.32m2 pack), and 100mm (2.88m2 pack). These thicknesses are indicative of the slab before it has been installed. As these slabs are semi-rigid, they can be compressed to fit into tighter spaces, e.g. partition walls or floor space. In practice, these semi-rigid slabs can compress by up to 10% of their starting thickness.

Always consult with a professional tradesperson to assess which thickness is most suitable.

Benefits of Rockwool RWA45 Slabs

Rockwool has over 80 years of experience manufacturing stone wool products, making them trusted experts in their field. They first introduced their thermal acoustic and fire insulation solution to the market way back in 1962.

One of the main benefits of using Rockwool insulation slabs is that they do not require any maintenance. Once you have installed the slab, you do not need to tend to them in any way - you can just simply slot them in and leave them be. And seeing as the semi-rigid slabs are made from long-lasting, water repellent materials, you can sleep easy – and dryly! – at night.

Another benefit of using Rockwool's high-quality resin bonded slabs is their A1 classification on the Euroclass scale. Euroclass A1 non-combustible is the best classification that insulation materials can achieve for combustibility and fire performance.

There are also Rockwool slabs with aluminium foil facings available, as well as black or white tissue. However, these come at an additional cost. Feel free to get in touch with our customer service team and they'll be happy to help you with specialist orders.

Frequently Asked Rockwool RWA45 Slab Questions

Frequently Asked Rockwool RWA45 Questions


Are Rockwool RWA45 Slabs Flammable?

Rockwool slabs are classed A1 on the Euroclass scale, which means they achieve the highest rating for non-combustibility and fire performance, and are completely non-flammable. If you were to hold a blowtorch next to a piece of Rockwool insulation, it might begin to glow but it will not catch fire or melt, making it an excellent fire barrier solution.

Where Can I Use Rockwool RWA45?

The slabs are perfect for application in walls, floors, stud partitions and lofts offering excellent acoustic, thermal and fire performance.
The slabs can be used for the following:

  • 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


Construction site managers also use RWA45 slabs in large commercial projects because they are easy to handle and efficient.

Lloyd’s register of shipping has also certified RWA45 slabs as approved non-combustible materials for fixed offshore installations and MED classed ships.

What Is a Rockwool RWA45 Data Sheet?

Rockwool data sheets tell you everything you need to know about the slab and its properties. Each product in our range comes with a data sheet written by the manufacturer so you get all the information from the horse's mouth. At a glance, these Rockwool data sheets will give you information about the thermal conductivity, density, thickness, W/mK, and important characteristics of each product.

How To Cut Rockwool RWA45 Acoustic Insulation Slabs?

Like the other slabs in the Rockwool range, RWA45 slabs are extremely easy to cut. We recommend marking the measurements you need on the slab before cutting so everything's nice and mapped out - preparation is key. You can use a utility knife or even a serrated knife to cut Rockwool slabs.

As always, we encourage our customers to take proper safety precautions during any general building projects. You should always use safety goggles and even gloves when cutting materials. We also advise cutting the slabs in a large, clear space with appropriate ventilation.