Cavity wall insulation, Home Insulation, SEAI Grants

Cavity Wall Insulation: 8 things you need to know.

It’s no surprise that cavity wall insulation, in combination with attic insulation, is the most popular form of work done by homeowners to upgrade the energy efficiency of their homes. Here’s the 8 most important things you need to know about cavity wall insulation before you consider doing the work or employing a contractor.

  1. You can benefit from at least €400 grant towards the cost of cavity wall insulation
  2. Cavity wall insulation is the most cost effective insulation upgrade.
  3. Insulation work needs to be carried out by a registered contractor to ensure that the fabric of your home is protected from damage.
  4. Most types of homes are suitable for cavity wall insulation.
  5. Cavity wall insulation upgrades are the least disruptive type of insulation work.
  6. Make sure you have a survey completed before you commit to any work.
  7. You will need to have extra ventilation installed when you upgrade your home’s insulation.
  8. Some older houses may not be suitable for cavity wall insulation.

1. If your home was built before 2006, there are grants available towards the cost of the work. 

Leitrim Warmer Homes, through the SEAI (The Sustainable Energy Authority of Ireland) offers grant funding for homeowners towards the cost of insulation and energy upgrades in pre-2006 built homes. These include:

  • €400 is available as grant funding towards the cost of cavity wall insulation.
  • An additional €400 grant is also available towards the cost of insulating your attic.
  • Having a BER (Building Energy Rating) assessment completed is a requirement of the grant funding but there is also an SEAI grant of €50 towards the cost of the BER assessment.
  • If you are in receipt of certain Department of Social Protection payments, you may be able to avail of FREE funding for energy saving upgrades to your home.
  • If you process your grant application through Leitrim Warmer Homes, you may be eligible for energy credits. This means that you will be able to combine the SEAI grant funding with the energy credits, giving you the maximum funding available towards the cost of the works.

The combined benefit of reduced heating bills and grant funding for the insulation work means many savvy homeowners are upgrading their home insulation and are offsetting the cost of the work against future (rising) heating bills. 

To find out how you can benefit from SEAI grant funding through Leitrim Warmer Homes, please click here .

You may be eligible for FREE attic and wall insulation under the Better Energy Warmer Homes Scheme. Click here to read more

2. Insulating your cavity wall is the most cost effective form of insulation.

With the rising cost of heating our homes in recent years, and with no sign of prices reducing significantly, many cost conscious consumers are biting the bullet and increasing the level of insulation in their homes. Insulating the cavity walls of your home and bringing your attic insulation up to building regulations standard of 300mm (12 inches) can save you €300 per annum or more in heating bills, depending on the size of your house. You can expect to recoup the cost of the work within  3 to 5 years.

While every house is different, you can expect to pay up to €11 per square meter for your house.

3. Make sure that your insulation work is carried out by a registered SEAI contractor.

Registered SEAI contractors, such as Leitrim Warmer Homes, are technically qualified and audited on a regular basis to ensure the highest quality standards in workmanship. As a registered SEAI contractor, Leitrim Warmer Homes will guarantee your cavity wall insulation for twenty five 25 years and you will be provided with a guarantee certificate when the work is complete. The certificate will detail the amount of insulation pumped into your walls, meaning that if you sell your home in the future, you can provide potential buyers with proof of the energy efficiency of your home.

4. Mid-terrace, end terrace, semi-detached and detached homes can all benefit from cavity wall insulation.

5. Cavity wall insulation is the least disruptive way of insulating your home.

Cavity walls are typically constructed of two “leafs” of cement blocks with an air gap of 100mm to 150mm between the leafs. This air gap is pumped with small polystyrene insulation beads. This type of insulation work is also one of the least intrusive in terms of the disruption caused to the homeowner. A series of small holes are drilled in the external wall at regular intervals. The insulation bead is pumped into the gap from the outside of the house and the drilled holes are then sealed. 

6. It is important to have an appropriate survey completed before undertaking any work.

A good surveyor will:

  • Survey your house to ensure that all work can be completed to the highest standards.
  • Be able to take into account the specific structure of your home and be able to advise you how the work will be conducted.
  • Be able to advise you on additional energy efficient measures that will increase your level of home comfort. For example, a good surveyor will check that your attic insulation is up to current building regulation so that you will not lose unnecessary warmth through your attic.
  • Provide you with a written quote detailing all the costs associated with the insulation work so that you can be satisfied with the final cost prior to the work starting and so that there are no surprises once the work is completed.

7. You will need extra ventilation installed when upgrading your insulation.

While sounding counterproductive, any insulation work carried out in your home will usually need extra ventilation installed to offset the increase in warm vapours leading to damp, mould or interstitial condensation. This does not make the insulation ineffective, rather, it protects the fabric of your home from deterioration.

8. Solid block or hollow block constructed walls are not suitable for cavity wall insulation as they have no cavity to pump.

You will need to insulate either the outside of the house (external “wrap”) or the inside of the walls (“dry lining”). If your house needs either external wrap or dry lining, you can also avail of SEAI grant funding.


You can call Leitrim Warmer Homes on 071 9640771 or email us on for further information or to discuss any insulation upgrades that you are considering. We are a local, trusted, registered contractor for the SEAI. We are independently audited to ensure that our work is completed to the highest standards, which means that our customers can be assured of the quality of our work. 

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