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.
*Please note we install Cavity Insulation only when required as part of a complete External Wall Insulation upgrade for your home and not as a stand alone measure.
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.
SEAI Grants Available
The Sustainable Energy Authority of Ireland (SEAI) offers generous grants for homeowners
installing EWI:
BlueBuild will support you through the grant application process from start to finish.
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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Great service from start to finish the whole team done a great job. The manager Sean Mcveigh helped me in every way, the whole team done a fantastic job i am very thankful to the whole team!
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I just had my house wrapped around by Blue Build and windows and doors replaced... From the beginning, I felt in safe hands, initially my home was assessed by experienced professionals, and a clear plan was put in place to address the problem area's.. Through out the process Tracey from the office kept me informed, reaching out to advise me of upcoming works around the time I was unavailable, this was a great help and stress relief..I met a number of team members and contractor's completing works, and of whom were friendly and approachable, and professional.. Works were scheduled regularly and area's cleaned and completed..I would like to give a Special recognition to Jason Roe whose commitment was evident at every stage he ensured that the work was completed to a very high standard, he was honest, explained thing's in plain language, Importantly he made me feel comfortable asking questions, no matter how small or straight forward they may seemed which is an excellent quality...It was a fantastic experience, and I would have absolutely no hesitation in recommending BlueBuild and Jason and his team to other's... A Big Thank You From Christine Cleary...
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I recently had work completed by BlueBuild Energy, Heath Pump, Radiators, Windows, Dashing. Jason Roe was project manager and maintained constant contact with myself and my wife. He explained everything and nothing was too much. He was very professional, friendly and extremely patient. Absolute gentleman. The lads who completed the job were very clean, tidy, mannerly and pleasant. The work was completed to a very high standard and I would have no hesitation in recommending this company. Dave & Geraldine Corrigan, Lucan, Co. Dublin
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I recently had my house installation from Bluebuild and what a company from Jessie in the office David the project manager the plumber Mickey and the crew of lads doing the work keep up the good work thanks again guys highly recommend 👍
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From the very first call from David, to the completion of job was fantastic. Excellent communication from David and a wonderful understanding of everything that was going to be carried out. All works were to an extremely high standard and ran to an exact time schedule. Amazing follow up also. Thank you David and all the team for a job well done. Elizabeth Stalton (Betsy) and Norah
Ready to Keep the Heat Where It Belongs?
Get professional, affordable insulation installed quickly — with grant support included.
• SEAI-Registered Contractor
• Fully Insured & Certified Installers
• 13+ Years’ Experience
• Customer Satisfaction Guarantee