Insulating homes all over Leinster


The Ultimate Guide to Cavity Wall Insulation in Ireland

Cavity wall insulation fills the spaces between inner and exterior walls to restrict airflow, boost efficiency, and reduce the cost of utility bills.

Cavity wall insulation is an effective way to reduce heat loss and save money on energy bills. It is also a relatively easy and cost-effective way to improve your home’s energy efficiency.

In Ireland, most homes built after the 1940s have cavity walls. This means that there is a gap between the inner and outer walls of your home, which allows heat to escape. Cavity wall insulation fills this gap with various materials that prevent heat from escaping, making your home warmer in winter and cooler in summer.

In this post, we’ll tell you everything you need to know about this type of padding and how you can benefit from it.

Let’s dive in.

What is Cavity Wall Insulation and How Does It Work?

In Ireland and other countries around the world, cavity wall insulation works by pumping certain materials into the cavity between the inner and outer walls of your home.

This technique helps prevent warm air from escaping through the cavity while keeping the area warm and cosy.

Bonded Bead Insulation

Bonded bead insulation is the most common type of cavity wall insulation. It’s made from expanded polystyrene (EPS) beads.

The material transforms into small beads that are then bonded together with a water-resistant adhesive. Then, the insulation material is injected into the cavity through small holes drilled in the outside walls.

This type of is relatively easy to install and is a more suitable option for homes with narrow cavities. It is also a relatively inexpensive option, and it is easy to install.

How to Tell if You Have a Cavity Wall that Needs to Be Insulated

Cavity wall insulation is a good way to prevent heat from escaping through your home’s walls to boost its thermal efficiency and lower utility bills. It is suitable for most homes with unfilled cavity walls, and it can be installed without causing any major disruption.

If you are considering cavity wall insulation, you need to first determine whether your home is suitable for this type of thermal insulation by doing the following:

1. Look at the External Walls of Your Home

If you can see the ends of bricks in the outer wall, you have a solid wall. However, if the bricks are laid evenly lengthways in a simple alternating pattern, it’s likely that you have a cavity wall.

2. Listen for a Hollow Sound

Tap on the external walls with your knuckles. If you hear a hollow sound, this means there’s an empty space behind it. If you hear a solid sound, then it’s more likely that you have a solid wall with no cavities.

3. Check Your BER Certificate

Your BER certificate will tell you if your home has cavity spaces. The BER certificate is a document that rates the energy efficiency of your home. It is usually issued by a qualified assessor.

The minimum cavity width in Ireland is 90mm for two-storey homes and 140mm for three-storey homes. If the empty space in your walls is narrower than this, then you may be eligible for a grant from the Sustainable Energy Authority of Ireland (SEAI) to have it insulated.

Here are some additional tips for determining if you have a cavity wall in Ireland:

  • If your home was built after 1920, it is more likely to have cavity walls.
  • If your home has rendered walls, it is less likely to have cavity walls.
  • If you have a fireplace or chimney, it is less likely to have cavity walls in the area around the fireplace.

If you are still unsure whether or not you have cavity walls, you can always contact your local authority or an energy efficiency assessor. They will evaluate your home and provide you with more information and advice.

What to Expect During and After Installation

Prior to installation, the contractor or installer will inspect your walls to check that they are suitable for cavity insulation.

Then, once they’re deemed suitable, here is what you can expect during and after cavity wall insulation:

During the Installation

  • The insulation installers will drill small holes into the exterior walls, typically at 12-18 inch intervals.
  • They will then blow or inject insulation between the cavity wall insulation boards, using loose-fill
  • The holes will be filled with a sealant to prevent moisture from entering the cavity.
  • The entire process typically takes 1 day.

After the Installation

  • You may notice a slight decrease in the amount of noise you hear from outside.
  • Your home should be more energy-efficient, meaning you may see a decrease in your heating and cooling bills.
  • The insulation may also help to reduce condensation and mould growth.

Factors to Consider

If you are considering having thermal cavity wall insulation installed in your home, there are a few things you should keep in mind.

Take a look.

Pumped insulation can be slightly more expensive, reaching around €8.50 and €13 per metre.

Here are some factors that can affect the cost of cavity insulation:

The size, condition, and location of your property

For example, a small mid-floor flat with two external walls might cost around €410 to insulate, while a detached house with four external walls could cost around €2,500.

The installer

The installer you use will also affect the cost. Some installers charge a fixed price per metre squared, while others charge an hourly rate. It’s important to get quotes from several installers before you make a decision.

The location of your property

The cost of labour and materials varies from region to region, so the cost of insulated cavity walls will also vary. Plus, if you live in a colder climate, the cost of cavity wall insulation will be higher because more insulation is needed to achieve the desired level of energy efficiency.

The condition of the walls

If your walls are in poor condition, they may need to be repaired before insulation can be installed. For example, if your walls have cracks or holes, these will need to be filled before insulation can be blown in.

Qualify for a Government Grant

If you are considering cavity wall insulation for your home, I recommend that you start by getting quotes from a few different contractors. You should also make sure that the contractor is qualified to install cavity wall insulation and that they use high-quality materials.

There are a number of government grants available to help you pay for cavity wall insulation in Ireland. The Sustainable Energy Authority of Ireland (SEAI) offers grants of up to €1,700 for cavity wall insulation.

To qualify for the grant, your home must be built before 2011 with insulation and heating control systems. It must also have an Energy Performance Certificate (EPC) rating of E, F, or G.

Other government grants and schemes that can help pay for cavity barriers are the Energy Company Obligation (ECO) scheme and the Green Homes Grant.

Ask about the warranty

The installer should offer a warranty on their work. You should also get everything in writing, including the scope of work, the price, and the warranty.

By following these tips, you can be sure to find a reputable cavity wall insulation installer who will do a good job and who you can trust.

Get a Quote

Here are some steps on how to get a fair and accurate quote on cavity wall insulation in Ireland:

1. Be prepared

Before you get a quote, be prepared to provide the installer with some information about your home, such as the size of your home, the type of insulation you want, and the location of your home.

2. Find a reputable installer

You can use the tips I mentioned earlier to find an installer or contractor who comes highly recommended.

3. Get a quote

Once you have found an installer, ask them for a quote. The quote should include the following information:

  • The size of your home
  • The type of insulation that will be used
  • The cost of the insulation
  • The cost of installation
  • The warranty

4. Compare quotes

Get quotes from at least three different installers so you can compare prices and services.

5. Make a decision

Once you have compared quotes, make a decision about which installer you want to use.

6. Get everything in writing

Once you have decided on an installer, be sure to get everything in writing, including the scope of work, the price, and the warranty.

Decide If Your Home Can Benefit from Cavity Wall Insulation

To be suitable for cavity wall insulation, your home’s cavity walls must be at least 50mm wide, and clear of rubble. The masonry or brickwork of your property should also be in good condition. If your home has narrow or uneven cavities, is on an exposed site or there is a risk of flooding, then it may be possible to fill the cavity with polyurethane foam.

Start by getting a quote from a qualified contractor or insulation installer. They will be able to assess your home’s suitability for insulation and recommend the best type of insulation for your needs.

Here are some of the factors that an installer will consider when assessing your home’s suitability for cavity wall insulation:

  • The width of your cavity walls and whether they’re uneven or consistent
  • The condition of your masonry or brickwork
  • The presence of any rubble or debris in your cavity walls
  • The exposure of your home to the elements
  • The risk of flooding

The Benefits of Cavity Wall Insulation

Cavity wall insulation is an excellent and affordable way to save on your energy bills and improve the comfort of your home. However, it is critical that you have it installed by a qualified installer to ensure a seamless process.

Here are some of the benefits of cavity wall insulation:

Reduced Energy Bills

Cavity wall insulation can help to reduce your energy bills by up to 25%. This is because it prevents heat loss, which means you need to use less energy to warm your home.

Plus, your home heats faster and stays warm for longer, thus lowering your carbon footprint.

Improved Energy Efficiency

Cavity wall insulation can make your home more energy efficient, which can help to reduce your carbon footprint.

Moisture Control

Cavity wall insulation can help to control moisture in your home, which can help to prevent mould and mildew growth.

Increased Comfort

Cavity wall insulation is guaranteed to keep your home warmer in winter and cooler in summer. This can make your home more relaxing to live in and improve your comfort levels.

Improved Air Quality

Cavity wall insulation works to improve the air quality in your home by reducing draughts. This can help reduce the risk of respiratory problems.

Increased Property Value

A well-insulated home is likely to be well-protected from the elements, and thus worth more than one that is poorly insulated. This is because a well-insulated home is more energy efficient and, therefore, more attractive to buyers.

The Potential Risks of Cavity Wall Insulation

If you are considering having your cavity walls insulated, be sure to do your research and weigh the pros and cons carefully before making a decision. Then, choose a qualified installer to avoid any potential setbacks.

The disadvantages of cavity wall insulation may be relatively minor. Still, it is important to be aware of them before installation.

Moisture Problems

If your home has any moisture problems, such as rising or penetrating dampness, cavity wall insulation can make the problem more severe. This is because the insulation can trap moisture in the cavity, which can lead to mould growth and other damage.

Plus, the effectiveness of cavity wall insulation can vary depending on the climate in your area. For example, it may not be as effective in areas with high rainfall or high humidity.

Structural Problems

Cavity wall insulation is not suitable for all homes. In general, this type of padding is not suitable for homes with cavity walls that are less than 50mm or more than 150mm wide.

If the insulation is not compatible with the overall construction, it can cause structural damage.

Installation Problems

If the insulation is not set up correctly, it can lead to problems such as gaps, voids, and even damage to the walls. This is why it is crucial to choose a reputable installer with experience in cavity wall insulation.


The overall price of cavity wall insulation can vary depending on the size of your home and the type of filling you choose. However, there are a number of government grants available to help offset the cost.

To Sum Up

As you can see, cavity wall insulation can greatly boost your home’s energy efficiency to make your home breezy in the summertime and toasty in the winter. As a result, you’ll start to lower the cost of utility bills and reduce your carbon footprint.

If you are thinking about getting cavity wall insulation for your home in Ireland, I encourage you to do your research. Also, make sure to get quotes from a few different contractors until you find the best one that meets your needs and budget.

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