Using the right insulation in the right application

By Knauf Insulation UK & Ireland
November 04, 2021

Insulation is one of the main contributors to maintaining a comfortable environment in your building all year round, enabling you to protect against cold in winter and warmth in summer. However you cannot use any product in any application; you have to use the products designed for each area of your build.

Each insulation product has specific properties that make it suitable for certain applications. Therefore, it is very important when choosing your insulation, to make sure that you are buying the correct insulation for the application.

A major factor to consider is whether Glass Mineral Wool or Rock Mineral Wool products are better suited for your project. Glass and Rock Mineral Wool are created with different applications in mind. Rock Mineral Wool products are manufactured to have slightly shorter fibre strands which give a far superior compressive strength. This is why products for flat roofing applications for example, which may be walked on during installation or maintenance, are manufactured from Rock Mineral Wool as opposed to Glass Mineral Wool.

However picking the correct insulation isn’t just a choice between Glass and Rock Mineral Wool, within each material group there are also important considerations to be made.

Using the correct insulation in the correct application is important to achieve the required performance, and meet customer and regulatory standards. An example of this is in a masonry cavity wall. In this application it is likely that some moisture will appear within the cavity, so you need to ensure a product that is manufactured with a water repellent additive is used. This is why we would recommend using DriTherm® Cavity Slab, as the product is designed specifically for this purpose.

Some applications require a product that has been manufactured to a certain density – for example if you are insulating an internal wall between plasterboards, you need a product that is 10kg/m³ to be in line with Approved Document E of the Building Regulations. This makes Acoustic Roll suitable for this application because on top of its superior acoustic properties, it is also manufactured to at least 10kg/m³ whereas a product such as Loft Roll wouldn’t perform in this application due to its lighter density and lack of acoustic performance.

The potentially biggest consideration however when choosing your insulation is the thermal performance. Each application will have a value for the level of thermal performance required as per the Building Regulations; it is important to find which value is required before your build. A good way of ensuring that you are going to be thermally compliant is to go for the best performing product for the application. You will be able to find this out by looking at a products Lambda; the lower the Lambda, the better performance the product will provide.

Finally it is crucial to understand what your product’s fire performance is, as each insulation material will have a level of fire resistance and the better the performance the safer a building will be. Using non-combustible materials minimises the risk that the building fabric will contribute to the development of the fire or contribute to fire spread should it occur. All our Glass and Rock Mineral Wool products have the best non-combustible Euroclass reaction to fire classification of A1 or A2-s1, d0.

So before you start your build, make sure that you understand what the main requirements of each application are. Depending on whether you are looking for fire, thermal or acoustic performance, your requirements will define which product you will need to use.

We have an extensive range of Glass and Rock Mineral Wool insulation products to cover every application for new builds and retrofit projects, whether residential or commercial. To find out which Knauf Insulation product is right for your project visit