A Guide to Internal Wall Insulation

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What is internal wall insulation?

It is important to understand just what internal wall insulation is before we go into detail about the benefits of fitting the insulation into a property and the various materials that can be used for the work.

Sometimes referred to as just internal insulation, this work involves insulation being applied to the interior face of external walls with the intention of improving a building’s thermal performance.

This is achieved as the insulation forms a thermal barrier on inner walls, which reduces how much heat is lost from a property and therefore enables an indoor temperature to become more stable.

Internal wall insulation often extends from the very bottom of a property all the way up until it meets any loft insulation that is also installed.

It should be mentioned at this point that internal wall insulation can be applied to just part of a property. The problem with this though is that the amount of moisture in the air will increase as a building’s internal temperature rises. This can result in condensation forming and mould growing in colder parts of a property – areas which are not currently insulated, for example.

Therefore, it should be recommended that an entire interior of a building receives internal wall insulation as a long-term project.

Internal wall insulation materials

As you will see when browsing through our internal wall insulation range alone, there is plenty of variety when it comes to the materials used for the work.

Here are some popular choices and the reasons why they each prove so appealing:

• Mineral wool – Examples of which include rock wool or glass wool being used in a property. This fibrous material in general is popular as there are options with sound-absorbing and fire-resistant properties.
   

• Natural fibre – An appealing choice due to it having lower embodied energy and delivering excellent levels of breathability, this material includes sheep’s wool, hemp and wood fibre. 
   

• Phenolic foam – The go-to choice when saving space, this material achieves low thermal conductivity and is an efficient insulator.
   

• Rigid boards – Low thermal conductivity and high levels of insulation can be achieved from thin panels of materials such as polyisocyanurate (more commonly known as PIR) and polyurethane within this category.
   

• Rigid foam – The likes of extruded polystyrene, expanded polystyrene and PIR are included in this category, with the material available in various thicknesses and provide impressive levels of thermal resistance.

Is internal wall insulation worth it?

The following are just seven reasons why you should recommend internal wall insulation to property owners:

1. It improves the level of comfort when in a property, due to indoor temperatures becoming more stabilised.

2. It minimises heat transfer around a property, meaning property owners benefit from lower heating costs.

3. It helps property owners to reduce their carbon footprint.

4. If natural fibre is used, it can help a property achieve better indoor air quality as the material can trap allergens.

5. It can increase a property’s value.

6. It is a more affordable choice than external insulation.

7. It is a suitable choice for properties built in conservation areas, where it may not be possible to alter the appearance of the building’s exterior.

By reading this guide, you should now have plenty of knowledge for recommending internal wall insulation. Have you also read our loft insulation buying guide and our advice on five things you should know about loft insulation?