What is Cavity Wall Insulation?
Many Irish homes built from the 1930s onward were constructed with two external walls and a gap (cavity) between them.
Cavity wall insulation fills that gap with high-performance insulating material, helping your home retain heat, lower heating costs, and feel noticeably warmer — often immediately.
The result? Warmer walls, reduced heating bills, and a more comfortable home — all in a day’s work.
Why choose Cavity Wall Insulation?
Is My Home Suitable?
We recommend a free survey to confirm suitability, but generally:
- Homes built from the 1930s and early 2000s
- Walls with unfilled cavity gaps (typically 50mm+)
- External walls in good structural condition
- Detached, semi-detached, or end-of-terrace houses
Homes with solid walls (pre-1970s) may be better suited to External Wall Insulation.
Our Installation Process
Our expert installation is fast, clean, and typically completed in just one day.
Here’s how it works:
- We carry out a detailed wall assessment to confirm suitability
- Small, discreet holes are drilled in the external wall
- High-performance insulation beads are injected to fully fill the cavity
- All drill points are carefully sealed to match the original finish
Extraction & Removal of Old Insulation (When Required)
Not all homes have clean, empty cavities. Some contain old, poorly performing, or failed insulation — such as mineral wool, or degraded foam.
Before we install new insulation, our team can fully assess and remove unsuitable material when needed. This ensures:
- The cavity is clean and unobstructed
- New insulation fills the space evenly and effectively
- Moisture issues caused by old insulation are eliminated
- You receive maximum thermal performance from your upgrade
Our extraction service includes:
If your home has cold patches, damp spots, or previously failed insulation, extraction may be the first step in restoring comfort and efficiency.
Northern Ireland Grants for Cavity Wall Insulation
Homeowners in Northern Ireland may be eligible for support through a range of government-backed energy efficiency schemes — helping to reduce or even fully cover the cost of installation.
Available support can include:
- NISEP (Northern Ireland Sustainable Energy Programme) – including fully funded options for eligible households
- Affordable Warmth Scheme for lower-income homes
- Potential support through local council or energy supplier initiatives
Our team will:
Assess your eligibility during your free survey
Guide you through the most suitable funding options
Handle the application process where applicable
👉 Find out if you qualify for fully funded insulation on our Residential Grants page.
Frequently Asked Questions on Insulation for your home
We’ve answered some common questions to help you with any concerns
Not at all. It’s a low-impact process with no interior work needed. All holes are sealed to match your wall.
Installed correctly, cavity wall insulation can last for the life of the building — 30+ years.
That’s what our free survey is for. We’ll carry out wall inspections and even use a borescope if needed.
Yes — and it’s highly recommended for best results and full grant benefit.
Our Installation Process
To check wall type and insulation potential
We prepare and submit your application
Using small drill points
Insulation fills the cavity wall completely
Wall finish restored to match original
Most installations completed in 4–6 hours.
Hear from Our Customers
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We decided we wanted to get a solar system for the house. So first things first did a bit of research online on local solar companies I had three different companies give me a quote. One of these companies was Bluebuild. First I had a call from a lovely guy called Ian Millar he came to have a look round my property then he sent me through a full layout of what would take place should I go with them. After speaking to the other two companies I found Ian to make the most sense plus I wanted to go with panels on the front and back of the house but Ian insisted that I ONLY needed 12 on the front. This in its self proved that they weren’t money grabbers they told you the truth this is VERY hard to get in this day and age. Anyway I decided that bluebuild was the guys to go with and I’m so glad I did … what a genuine top company I would have given them ten stars… from the guys with the scaffolding arrived to the full install was carried out all totally professional people and all nice guys to boot. Saving on my electric already…I am a very sceptical person and find it hard to trust anyone honestly if your thinking about going down the solar route please don’t go anywhere else this company has to be the best in the six counties. Thanks again Bluebuild👍👍😃👍👍
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Bluebuild Energy recently insulated my house and upgraded my heating system. I would highly recommend Jason and his team. They were so efficient and professional. 5 stars from me.
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From the very beginning, we have had excellent communication with Bluebuild. Vassily and his team are very hard workers and Fionn did a great job in the attic. Jason ensured that everything was reinstated perfectly. We are delighted with the job....... Michael and Jenny, Co. Wicklow
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From start to finish,the team were all excellent. All work done was completed to a really high standard. Jason went above and beyond in ensuring that the work was done quickly and professionally. I cannot recommend Bluebird enough.
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Just had Bluebuild install a new solar PV and Battery system at our home on North Coast. The process was fantastic from start to finish. Competitive pricing, simple admin and speedy installation. 16 panels over two adjacent roof sections with 2 Dyness 5Kw batteries and a Solis Inverter. Everything is up and running, I’m looking forward to the spring to see it at its full potential. Would definitely recommend Bluebuild Energy Ltd. I had received quotes from a number of companies before settling on Bluebuild who were the most competitive and research recommended them as one of the most experienced and longest established.
Ready to Keep the Heat Where It Belongs?
Get professional, affordable insulation installed quickly — with grant support included.
• IAA -Registered Contractor
• Fully Insured & Certified Installers
• 13+ Years’ Experience
• Customer Satisfaction Guarantee