External Wall Insulation

External wall insulation wraps the outside of your home block thermal leaks and leaving you and your family warmer.

Solid walls don’t trap heat efficiently and twice as much heat can escape through them as through cavity walls. Upgrading them with external wall insulation is a great idea, as not only will you save on your energy bills, but you’ll also protect your home by preventing damp and give the exterior a makeover.

Whilst insulating cavity walls is a quick and relatively cheap process, the insulation of solid walls can prove to be quite a bit more expensive. For a free quote, complete the form above.

What’s In This Guide?

Head straight to the section you need by clicking the links below.


What Is External Wall Insulation & Is My House Suitable?

Most British homes built before 1930, were built with solid walls, leaving no cavity that can be filled with insulation. These houses can still be brought up to modern standards by insulating the external walls and improving the building seal. This method of home insulation reduces heat loss and, depending on the finish used, protects against the elements.

We wrote extensively on how to test if your home has solid walls or cavity walls here.


The Insulation Process

  1. Adhesive mortar is used to fix the prefabricated insulation panels to the outside wall.
  2. Special fixings are used to secure the panels to the wall.
  3. The insulating panels and fixings are then covered in mortar.
  4. An insulating mesh is then fixed to the mortar to hold everything in place safely.
  5. Once the mortar sets, it’s sanded and painted in primer to prepare for the final stage.
  6. A render and colour is applied as per the clients choice.

The first step is to check if your home has an existing external surface or render. If this surface is able to support the external insulation it can be applied directly and reduce the cost of the process. Should your existing external wall surface be unable to support the new layer, it must be removed down to the brickwork.

All external pipework, satellite dishes and obstacles must be removed prior to installing external wall insulation. This can be time consuming and is one of the reasons this process of home insulation is more expensive.


External Home Insulation: The Savings

These figures are estimates based on averages. The savings you will see will depend the existing level of insulation in your home and home heating system.

How Much Does External Wall Insulation Cost?

The cost of external insulation of solid walls is about £120 per square metre. So, insulation of small apartments will cost in the region of £9,500, while insulating a large detached house can come to around £25,000. The investment will repay you over time but the not for several years. The price of external insulation can range significantly depending on various factors. For example, the scope of work, the accessibility of walls, etc.

Internal insulation costs are generally lower and ranges between £4,500 and £18,000. However, the payback period is still quite long.

External Wall Home Insulation Grants

Grants are available for external insulation through the SEAI.

External Wall Insulation: Considerations

To install the external insulation a layer of insulating material will have to be fixed to the wall with the help of mechanical fixings and covered with shielding layers of plaster covering or cladding. Usually, plaster covering is cheaper than the cladding.

External wall installation can be done quickly if the outside of your house is suitable and depending on the design.

However, if the existing coating of your building can’t support the insulating layers or is cracked, it will have to be removed or fixed which can increase the cost of the project.

If your building is a period property and you want to improve its appearance whilst increasing the heating efficiency, you may be advised to use custom insulation solutions. For this type of insulation, various materials can be used. They include stone, glass, terracotta tiles or oak weatherboarding.

It is vital to ensure that there’s no penetrating damp inside the walls before installing the external insulation. Even though the damp can be temporarily covered with the wall insulation, the problem will keep growing.

External insulation will be most beneficial when paired with other energy efficient home improvements such as double glazing and spray foam insulation of the attic or loft.


External Insulation: The Advantages

External insulation is less disruptive than an internal solution but you may have to cut your gas or electricity for the building period.

You won’t loose any space in your home.

The appearance of your external walls can be improved because you can choose from a wide variety of finish types. For example, it can be smooth or textured, painted, tiled, etc. It can also be faced in wood, aluminium panels, brick, or tiles.

With external wall insulation, your home will become more weather resistant and soundproof.

The draughts in your house will be reduced and you will have an improved building seal.

Because insulating material fills all the gaps in the building seal, it lowers the risk of getting condensation and mould inside the walls.

The Disadvantages

There is no getting around it, external wall insulation is expensive. Therefore, the best way to plan the time for installing it is by combining it with other external work that is necessary for your house. By doing so, you will be able to reduce the cost.

If your house is situated in a terrace, there may be the need for scaffolding as the installers will need easy access to the external walls of your home.

In order to install the external wall insulation, your walls have to be in good condition. Therefore, if your outside walls are old and can’t be repaired, then this type of external insulation won’t be suitable.

Period homes and properties won’t always be suitable and depending on the property there may be regulations protecting the building.

Before installing the external insulation, all of the exterior units such as satellite dishes, pipework, or security lights have to be removed and then replaced, adding to the cost.

The roof eaves and window sills will have to be extended so that they fit the thickness of the exterior wall.

Related Posts

Scroll to Top