4.8 out of 5 Stars on TrustPilot

Rockwool Insulation – the ultimate guide

If you’re considering an external wall insulation project, you might have come across the term ‘mineral wool’. This is a high-performance type of insulation material made from stone or glass fibres. Mineral Wool is often referred to as ‘Rockwool’.

Rockwool is best-known for being non-combustible (fireproof), but it also has many other great features!

In this blog, we’ll take a look at some questions you might have about mineral wool insulation. We’ll outline what mineral wool is, its features and benefits. Consider this your ultimate guide to Rockwool Mineral Wool Insulation!

Read on to find out more about Rockwool insulation!

What is mineral wool?

Mineral wool is a type of insulation material that is made from stone and minerals that have been spun into strong fibres. As you can imagine, being made from stone fibres means that mineral wool creates a high-strength and durable thermal insulation material.

There are two main types of mineral wool – fibreglass wool (made from glass fibres) and stone wool (made from stone or rock fibres). Both are derived from natural materials, and therefore are naturally resistant to the elements. This blog post will focus on stone wool insulation – specifically Rockwool.

Let’s find out more about this type of insulation!

What is Rockwool?

When considering mineral wool as an insulation material, you may have come across ‘Rockwool’. But what is it and is Rockwool the same as mineral wool?

Rockwool and mineral wool are the same. Rockwool is simply a brand of mineral wool insulation; it has simply become synonymous with mineral wool.

A unique feature of Rockwool insulation boards is that they are 3 times denser than fibreglass batts. This makes them a sturdy and long-lasting way to insulate your home.

At EWI Store, we stock Rockwool dual-density slabs – which are designed specifically for EWI systems. This means that the top layer of insulation is a higher density than the rest of it. This creates a suitable and even surface to render onto.

Let’s look at some of Rockwool’s unique features!

Rockwool features

Rockwool is a high-performance type of stone wool. It is one of the best insulation materials available on the market. Rockwool uses naturally derived minerals to provide high-strength, durable, and non-combustible thermal insulation to buildings.

Below is a breakdown of Rockwool’s unique properties:

  • Fire: Euroclass A1 – non-combustible.
  • Thermal: 0.036 W/mK.
  • Strength: Tensile strength perpendicular to faces ≥ 10 kPa.
  • Acoustic insulation: reduces noise pollution.
  • Breathable.
  • Water-resistant.
  • Sustainable: 97% recyclable and long-lasting.

These incredible properties make Rockwool a great material for largescale, commercial projects – not just residential homes. This is why it is becoming increasingly popular among architects, as it provides an overall high level of safety and protection to your home.

Is Rockwool fireproof?

Yes! Rockwool is completely fireproof!

Fire resistance is valid concern for many homeowners and installers of commercial projects. Therefore, you will be glad to learn that Rockwool is indeed fireproof. In fact, Rockwool mineral wool insulation boards have the highest possible fire rating (Euroclass A1) for non-combustibility. This means that in the case of a fire, it won’t burn or contribute to the fire.

As such, Rockwool is an incredibly safe external wall insulation material and has therefore become increasingly popular among architects and largescale. Investing in mineral wool as your chosen insulation material, will give you peace of mind knowing the exterior of your building is protected from fire.

Another key feature of Rockwool slabs that was mentioned earlier is that it provides excellent acoustic insulation.

Is Rockwool good for soundproofing?

This means that Rockwool (and mineral wool generally) is great for soundproofing your building! Soundproofing is especially useful in areas of high traffic and noise pollution, such as urban areas or next to roads.

So, if you’re looking to reduce noise pollution to your home or building, Rockwool is a really great option that comes with many other benefits too!

How to install a Rockwool EWI system

As mentioned, Rockwool is a really great and versatile insulation material. It is also easy to install and is compatible with many other EWI products. Let’s look at how you would go about applying it to a substrate.

You should always apply primer to your substrate before installing mineral wool insulation. Use the EWI-310 Universal Primer on smooth substrates and the EWI-301 Water Based Primer on brickwork.

Then, install a starter track, and follow with EWI-225 Premium Basecoat. We recommend that you apply Premium Basecoat around the perimeter of the Rockwool slabs and 3 dabs in the centre. This way, you can achieve an even surface before rendering!

You can read more about rendering onto Rockwool Mineral Wool insulation in our complete guide!

  • Premium Basecoat EWI-225
    Quick View

    Premium Basecoat (EWI-225) – 25kg

    £19.36 Excl. VAT
  • Universal Primer EWI-310
    Quick View

    Universal Primer (EWI-310) – 20kg

    £60.03 Excl. VAT
  • Water Based Substrate Primer EWI-302
    Quick View

    Water Based Substrate Primer (EWI-301) – 5 Litres

    £15.74 Excl. VAT

Is Rockwool sustainable?

You might be surprised to learn that Rockwool insulation is actually one of the most sustainable external wall insulation materials available on the market.

Rockwool are a company committed to sustainability and improving their environmental impact. This means that all Rockwool products are made with sustainable materials and practices in mind. For example, Rockwool insulation is approximately 97% recyclable!

Rockwool mineral wool is made from naturally occurring materials. This means that it doesn’t release any environmentally harmful, ozone-depleting greenhouse gases.

Not only this, but Rockwool’s incredible fire-proofing qualities make it a highly sustainable material too. This is because a building fire pollutes the immediate environment with large volumes of harmful gasses and chemicals. This depletes the o-zone layer, but also affects residents nearby. Rockwool’s fire safety features ensure this will not occur.

Therefore, Rockwool mineral wool is an excellent option for those who are looking for a safe and environmentally friendly insulation material.

Find out more!

Want to find out more about the mineral wool installation process? Check out our complete guide! This walks you through the installation process and highlights the materials required for the system.

Don’t feel like reading? Give us a call on 0203 0340022, one of our sales representatives will be happy to assist!

Check out the coverage rates of our mineral wool insulation boards below:

Thickness of board (mm)Coverage per pack (m2)


Leave a Reply

Your email address will not be published. Required fields are marked *

Read more here!