1️⃣ Endoscopic Inspection
The technician drills a small hole and inserts a camera inside the wall to confirm the cavity is clean (no construction debris) and has sufficient width (at least 4-5cm).
Insufflation Method - The "Invisible" Insulation for Existing Wall Cavities
In Greece, a huge percentage of buildings constructed in the 1970s and 1980s were built using the cavity wall method. Masons would build the inner wall, leave a 5 to 10cm air gap, then build the outer wall. At the time, many mistakenly believed that "trapped air insulates on its own", so they never placed insulation material in the middle.
If you live in such a house, you have a "lottery ticket" waiting to be cashed. You don't need to clad the house inside or out. You can simply fill that void using the blow-in insulation (insufflation) method. Let's see how this "invisible" and impressively fast renovation works.
1. What Is the Insufflation Method: The Surgical Process
Insufflation is a specialist procedure in which a team fills the empty cavity of your wall with loose insulation material, using air-pressure machines (compressors). The process is almost surgical:
2️⃣ Drilling
Small holes (2-3cm diameter) are drilled into the wall, either from the external or internal side, at specific intervals.
3️⃣ Material Injection
Through a hose, the machine "blows" insulation into the wall under high pressure. The material swirls and fills every crack, corner and void, from bottom to top.
4️⃣ Sealing
The holes are filled and painted. Within hours, it's as if the team was never there!
2. Materials Used: Loose-Fill Insulation
We can't insert rigid boards into the wall, so we use loose-fill materials:
🧲 Polystyrene Beads (EPS / Neopor)
They look like tiny balls. Often mixed with a special adhesive at the nozzle, so once inside the wall they bond together forming a solid, impenetrable mass that doesn't settle over time.
🪨 Rock Wool / Glass Wool Flakes
An excellent solution offering top-tier thermal insulation, sound insulation and absolute fire protection simultaneously.
🌲 Cellulose
An ecological material made from recycled paper, treated with boron salts for fire and insect protection. Ideal for timber-frame constructions and roofs.
3. The 4 Major Advantages of Insufflation
Insufflation stands out as the easiest, fastest and most cost-effective insulation solution for existing buildings with wall cavities.
⚡ Zero Disruption
Forget scaffolding, planning permits, demolition and dust. An average detached house can be fully insulated in 1 to 2 days.
🏠 No Change to Appearance or Space
The house looks exactly the same externally (ideal for listed or stone buildings) and you don't lose a single centimetre of interior space.
🎯 Complete Sealing
Because the material enters under air pressure, it "embraces" pipes, cables and brick irregularities, sealing spots that rigid boards could never reach.
💰 Low Cost
Typically 30% to 50% cheaper than installing a full external ETICS system.
4. The 10x10 Model Experiment
Let's assume our digital house was built in 1985 as a cavity wall with a 6cm air gap in the middle (wall U-Value: 1.80 W/m²K). The house is an energy sieve.
📊 Insufflation Result
We call the insufflation team and fill those 6cm with graphite EPS beads. The brick wall U-Value plummets to 0.48 W/m²K! We've reduced heat transfer losses through the masonry by approximately 70%.
⚠️ Important Note
Although the wall is now perfectly insulated, the concrete beams and columns (which have no cavity) remain uninsulated. Energy will still leak there (thermal bridges). However, the overall improvement at such low cost and zero disruption is enormous.
💡 Conclusion: If your house has empty cavity walls, insufflation is the biggest energy "gift" you can give yourself. It is the smartest, best value-for-money intervention before you even consider external ETICS.
Related Articles
Cavity Wall Core Insulation: How It Works & Advantages Cavity Wall Moisture Management: Weep Holes & Ventilation Placing Extruded Polystyrene (XPS) Between the Bricks Thermal Bridges in Cavity Walls: Insulating Columns & Ring Beams
Insulation Systems: Complete Solutions for Every Building
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