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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June 2026 External Wrap, Cavity Wall and Attic Insulation. Chimney blocked and vents inserted in all of the rooms and attic. I would like to thank Tony, the project manager and Niamh in the office for such a good experience (and all the Bluebuild people who worked on our house). Bluebuild carried out all works in a timely, professional manner with minimum distruption. They organised everything and helped with the grant paperwork. I would have no hesitation recommending Bluebuild.
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Very happy with all works done 'lads were very helpful always ,worked very hard and long days to get our job done thanks to all who helped get our ho.e finished
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Fantastic service from Blue Build. The whole team did an excellent job wrapping our house. They were professional, reliable, hardworking, and the quality of the workmanship is outstanding. We couldn’t be happier with the finished result and would highly recommend them.
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We recently had external insulation installed on our home, and we couldn't be happier with the entire experience. The professionalism shown by everyone involved was outstanding. The quality of the workmanship is excellent, and the attention to detail is clear in the finished result. The installation crews were incredibly hardworking, friendly and courteous. They arrived early each day, worked efficiently, and were always happy to answer any questions we had. The management team were equally impressive. They were approachable, helpful and very accommodating throughout the project, making the whole process straightforward and stress-free. Nothing ever seemed like too much trouble. The work was completed much quicker than we expected, without any compromise on quality. The team also took great care to keep everything clean and tidy, leaving the property in excellent condition when the job was finished. We are absolutely delighted with the final result and would have no hesitation in recommending this company to anyone . A first-class service from start to finish. We'd like to specifically thank Michael, Colm, Lulian and his crew and Niamh the secretary!
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Had the most wonderful group of lads in to do the wrap fan s windows and attic insulation in my mum's house in wicklow town under the supervision of Jason roe project manager From start to finish a fantastic job the lads all very mannerly and plesent extremely tidy Could not rate them any higher Thrilled with the end result Thank you guys Andre and most of all Jason
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