External Wall Insulation is a comprehensive facelift for older homes which can provide greater protection from the cold and weather, while also giving it an attractive new appearance.

With its high thermal performance and the availability of insulation grants to offset the potentially high cost, external wall insulation is definitely worth it in Ireland for people seeking to renovate older homes.

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External Wall Insulation

Key Takeaways

  • External Wall Insulation, often referred to as a ‘Wrap’ for your home, is a system comprising multiple layers of material attached to the outside of a house

  • Up to 30% of a home’s heat can be lost through its external walls

  • If your house was built before the 1930s it is likely a solid wall, without a cavity space. Even if it was built after, it might not be suitable for cavity insulation

  • Types of external wall insulation:  Rolled Wool Insulation and Polystyrene insulation

What is External Wall Insulation

External Wall Insulation, often referred to as a ‘Wrap’ for your home, is a system comprising multiple layers of material attached to the outside of a house. When completed it should provide a new finish which is warmer, weatherproof, and with a much-improved appearance.

The innermost layer of the wrap consists of the insulation, which is mechanically affixed to the outside wall of the house. An adhesive bonding layer is then applied to the outside of the insulation with an embedded mesh before a final render is applied on top to provide an attractive finish.

External Insulation Wrap Components

  • Insulation: The innermost layer of either rigid boards of polystyrene insulation, or rolls of mineral or fiberglass wool.

  • Adhesive: A layer of adhesive solution is placed between the insulation and the render on the outside to bond them.

  • Mesh: A steel or fibreglass mesh will be embedded in the render to add strength to the entire construction/

  • Render: A final render is applied to the outside of the wrap in the colour and texture of your choice.

Installing external wall insulation may also require windows or window sills to be replaced depending on the property and the thickness of the wrap.

The thermal performance of the wall after installing insulation is measured by its U-value, expressed as W/m²K. This measures how much heat passes through an area, taking into account values in the complete project such as the thickness of the insulation layer, and other factors.

Should I Get External Wall Insulation

A poorly insulated home can be extremely expensive to keep heated, and this is particularly true of older buildings built to lower standards of energy efficiency than modern homes.

If your house was built prior to the 1930s it is likely a solid wall, without a cavity space. Even if it was built in the decades later, it might not be suitable for cavity insulation. 

In this case, an external insulation wrap will be your best option to add a layer of insulation to the outer walls of your home.

For older buildings external insulation can also provide a facelift with a new render in an appearance of your choice. All of this makes external insulation an ideal choice for older properties, especially those undergoing a complete renovation.

External insulation can also be installed alongside Cavity Wall insulation in some cases. This might provide an additional benefit if your wall only has a small cavity and you wish to increase its performance.

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Benefits of External Wall Insulation

If you are considering home insulation, consider the following benefits of external wall insulation.

While having external insulation installed is a big job, all the work takes place outside the house. This means that there will be minimal disruption to your daily life while work occurs.

Having a solid layer of insulation installed on the outside of the property means that there will be no loss of floor space inside your home, unlike with internal insulation.

The multiple layers of insulation and final render provide a weatherproof layer which protects your wall from the elements and damp.

Older properties will benefit from a completed transformed appearance once the final render is put in place. Installers typically offer multiple options in both colour and finish. This makes external insulation an excellent aesthetic renovation, as well as a practical one.

A solid masonry wall doesn’t provide the best insulation against noise from outside the house. The external insulation wrap will reduce that inconvenience.

Reducing the amount of heat lost through the external walls of your home can deliver significant savings from lower gas, oil, or electricity costs in heating the property.

Types of External Wall Insulation

The two main varieties of insulation used in an external wrap are either rolled wool or rigid boards. The two will differ in price and thermal performance, with different thicknesses needed to meet the U-value required by building regulations.

The most common and easiest to apply type of attic insulation. Rolled Wool insulation consists of layers of glass wool (fibreglass), wood wool, rock wool, or sheep’s wool which is rolled out, as the name suggests. Different materials will have different levels of thermal conductivity. 

Fibreglass and Rock wool also have the advantage of being very fire-resistant.

The most important factors to take into consideration are the density of the material being used and the thickness of the layers being applied. Both of which will affect how much insulation is provided. 

Polystyrene Insulation is a type of thermoplastic foam which comes in the shape of rigid boards. This is popular as a form of insulation due to its adaptability, ease of application, and excellent protection against heat loss and noise.

Types of External Wall Insulation

External Wall Insulation Cost

The cost of applying insulation to the exterior of a building will vary depending on several factors.

  • The size of the property
  • Insulation materials used.
  • The complexity of the property (e.g windows, vents, intricate design)
  • Accessibility

A house with many small areas, corners, and windows will be a more complicated job, driving up the labour costs. The price will also of course be higher if you have a larger home with a greater surface area to insulate.

Depending on the type of house you have, external wall insulation can cost anywhere from €10,000 – €30,000 excluding grant savings. These are only estimated ranges, and an assessment of your home is needed for an accurate figure.

External Wall Insulation Grants

The SEAI offers grant funding for private homeowners and Approved Housing Bodies to get external insulation installed. The size of the grant depends on the type of property you have, with larger grant values for AHBs.

For private homeowners grants of up to €8,000 are available from the SEAI, and AHBs can receive a maximum of €10,000.

The grants are available for all homes which were built and occupied prior to 2011.

Insulation Type Private Homeowner Grant AHB Grant
External Insulation (The Wrap) Apartment (Any) – €3,000

End-Terrace House – €3,500

Semi-Detached/End-Terrace – €6,000

Detached House – €8,000

Apartment (Any) – €3,500

End-Terrace House – €4,500

Semi-Detached/End-Terrace – €8,000

Detached House – €10,000

Note: Building regulations require that any alteration to 25% or more of a home’s surface area requires that it meet a minimum B2 BER rating or that the heating system and attic insulation comply with the Building Regulation standards. 

Any application for an external wall insulation grant from the SEAI requires that you meet these building regulations for it to be paid.

Homeowners availing of wall insulation grants from the SEAI are also required to see that the insulation achieves a U-value of 0.27 W/m2K


External Insulation may require you to seek planning permission if there will be a change to the appearance of the property. It may also not be possible if the building is located in a conservation area or is otherwise protected.

External Insulation attached to a property can be removed, but this is a costly and delicate process.

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