Cavity wall insulation removal in Dublin
Wet or slumped cavity fill has to come out before the wall can be insulated again. SEAI publishes no grant for taking insulation out; its wall grants cover putting it in. But if you've already claimed a cavity wall grant, you can claim a second time for external wall insulation, worth €6,000 on a semi-d.
- Free, and no obligation
- SEAI-registered contractors only
- Grant figures checked 15 August 2026
Can you get a grant once the old fill is out?
Usually yes. SEAI allows a second wall insulation measure, so a house that took a cavity grant years ago can claim again for the wall going back. That is normally worth more than the extraction costs.
So a semi-d that took €1,300 for cavity fill can take €6,000 towards external wall insulation now. Most Dublin houses end up there once the cavity's been emptied. The wall still needs insulating, and the cavity is off the table.
Source: SEAI wall insulation grants. Amounts and rules change. Confirm your own eligibility with SEAI before you commit to work.
SEAI's rule, in its own terms
- Cavity wall grant already claimed
- You can apply for internal or external wall insulation.
- Internal wall grant already claimed
- External only.
- External wall grant already claimed
- That is the end of the road for wall measures.
What the reinstatement is worth
| Home | External wall | Internal wall | Cavity (original) |
|---|---|---|---|
| Detached house | €8,000 | €4,500 | €1,800 |
| Semi-detached or end of terrace | €6,000 | €3,500 | €1,300 |
| Mid-terrace house | €3,500 | €2,000 | €850 |
| Apartment | €3,000 | €1,500 | €700 |
Why fill gets taken back out
A cavity wall is two leaves with a gap between them, and the gap is doing a job. Rain driven through the outer leaf runs down the back of it and drains away at the base, so it never reaches the inner leaf. Anything bridging that gap hands the water a path across.
Fill that's slumped, or got wet, or went into a wall that was never a good candidate can become that bridge. Taking it out is what lets the wall dry before anything else gets decided.
What people notice first
- Damp patches on an inside wall that come and go with the weather
- Cold spots
- Mould on a wall that used to be dry
- A room that got harder to heat after the fill went in, not easier
What the job involves
Most contractors call this extraction rather than removal. Same job.
Holes get drilled, or bricks lifted, and the fill is drawn out under vacuum, section by section, until the cavity's clear. A borescope goes in as they work. It shows what's actually down there, and whether mortar snots are holding material up where the vacuum can't reach it. Then the holes are made good and the wall is left to dry.
A wall emptied and refilled the same way, in the same conditions, is a wall you'll be emptying again.
Two questions for whoever quotes
How will they show you the cavity is actually empty at the end? A borescope goes in as they work, and it is the only thing that shows whether mortar snots are holding material up where the vacuum cannot reach.
What are they doing about whatever caused it? The extraction fixes the symptom. If nothing changes about how water gets into that wall, the next fill fails the same way.
No cost, no obligation
Get quotes for cavity wall extraction
Tell us about the house. We pass it to SEAI-registered contractors working in Dublin, and they come back to you with quotes. We're not a contractor and we never charge homeowners.
Five questions. Email and the notes box are optional.
Cavity wall insulation removal questions
6 questions
Why are people taking cavity wall insulation out?
Because the cavity has stopped doing its job. That gap exists to keep water that gets through the outer leaf away from the inner one. Fill that's slumped, or got wet, or went into a wall that was never suitable can bridge the gap, so damp tracks across to the inside instead of draining away. You end up with both problems at once: a damp wall, and insulation that's barely insulating, because wet material conducts heat instead of trapping it.
Is there an SEAI grant to remove cavity wall insulation?
None that SEAI publishes. Its wall grants are for installing insulation — cavity, internal or external — and there's no removal grant listed alongside them. Budget for the extraction yourself, then read the next answer, because the money is in what happens afterwards.
Can I get a grant once the old fill is out?
Usually yes. SEAI allows a second wall insulation measure. If you previously received a grant for cavity wall insulation, you can apply for an internal wall insulation grant or an external wall insulation grant. On a semi-d that's €6,000 towards external, or €3,500 towards internal. If your first grant was for internal insulation you can only move to external, and if you've already had an external wall grant, there's no further wall grant available.
What does cavity wall insulation cost in Ireland?
We don't publish a price, because quotes for the same house vary enough that a number here would mislead you more than help. Here's the half that is fixed: SEAI pays €1,800 towards cavity wall insulation on a detached house, €1,300 semi-detached or end of terrace, €850 mid-terrace and €700 for an apartment, with higher amounts if you're on a qualifying welfare payment. The quotes decide the rest.
How long does extraction take?
Ask whoever quotes, and be wary of anyone who answers before seeing the house. It comes down to wall area, what's actually in the cavity, and how easy the walls are to get at. A mid-terrace with a shared side and no rear access is a different job from a detached bungalow.
What happens to cavity wall insulation after 25 years?
There's no published expiry date, and age on its own isn't the problem. What matters is whether the cavity is dry and whether the fill is still sitting evenly. Materials behave differently over time, and a wall that was suitable, properly filled and well detailed can be fine decades later. A borescope tells you what's in there. The installation date doesn't.