Internal wall insulation in Dublin
Internal wall insulation, or dry lining, fixes insulation boards to the inside of your external walls. SEAI pays €4,500 for a detached home, €3,500 semi-detached or end of terrace, €2,000 mid-terrace and €1,500 for an apartment. It costs you 60 to 100mm off each external wall.
It's the measure for houses where the outside can't be touched, which in Dublin usually means a protected structure or a conservation area.
- Free, and no obligation
- SEAI-registered contractors only
- Grant figures checked 15 August 2026
What SEAI pays, by house type
The external grant is larger because the job is. SEAI describes external wall insulation as generally the most expensive option and internal as much cheaper, so the smaller grant doesn't mean you're worse off.
Source: SEAI wall insulation grants. Amounts change. Confirm before you commit.
Internal against external
| Home | Internal wall | External wall |
|---|---|---|
| Detached house | €4,500 | €8,000 |
| Semi-detached or end of terrace | €3,500 | €6,000 |
| Mid-terrace house | €2,000 | €3,500 |
| Apartment | €1,500 | €3,000 |
Median cost against the grant
| Home | Median cost | Grant | You pay | Grant covers |
|---|---|---|---|---|
| Detached house | €8,600 | €4,500 | €4,100 | 52% |
| Semi-detached or end of terrace | €9,843 | €3,500 | €6,343 | 36% |
| Mid-terrace house | €9,804 | €2,000 | €7,804 | 20% |
| Apartment | €5,736 | €1,500 | €4,236 | 26% |
Costs from SEAI's published median costs, checked 15 August 2026. SEAI calculates them from the figures registered contractors and One Stop Shops submit when a grant is paid, so they are what people actually paid rather than what anyone advertises.
One oddity in SEAI's own data, left as published: internal insulation has a higher median on a semi-detached house than on a detached one, and mid-terrace is higher again than detached. Every other measure runs the other way. Read the row for your house type rather than assuming a smaller house means a smaller bill.
When is internal the right choice?
Two clear cases, and one bad reason people pick it.
- The outside can't be altered. SEAI names internal insulation as the option "when you don't have a cavity wall and external insulation is not possible (for protected structures)". In Dublin that covers a lot of the red-brick stock through Rathmines, Ranelagh and Drumcondra, where the front elevation is the whole reason the house looks the way it does.
- You're redecorating anyway. The job ends in fresh plasterboard, skim and paint. If that was happening this year regardless, the marginal disruption is small and the grant is real money.
- The bad reason: it looks cheaper. It is cheaper, but you're paying in floor area and in weeks of your house being unusable. If external insulation is permitted on your house, price both before deciding.
What it costs you that external doesn't
60–100mm off the inside of every external wall
External insulation
Rooms keep their size
Wrapped, then rendered.
Internal dry lining
Rooms lose 60–100mm
Boarded inside.
In a small bedroom with two external walls you will notice it. Measure the rooms you care about before you sign, because this is the one cost external insulation does not have.
What the job involves
Insulation boards are fixed to the inside face of every external wall, then covered with a vapour control layer, plasterboard, a skim and paint. SEAI's own summary is that it's "quite disruptive and dusty".
What that means in practice: the rooms have to be cleared. Skirting boards come off. Electrical sockets and switches come off the external walls and go back on the new surface. Radiators fixed to external walls come off. Curtain poles, shelves and anything else screwed to those walls comes off. Then it all goes back, and the room needs decorating.
What comes off the wall, and goes back
- Skirting boards
- Sockets and switches
- Radiators fixed to external walls
- Curtain poles, shelves, anything screwed on
Then the room needs decorating. SEAI's own summary of the job is that it is "quite disruptive and dusty", which is why doing it while you are redecorating anyway is the cheapest version of it.
The whole-surface rule applies here too
You can't insulate one cold room and claim the grant. SEAI requires a whole-surface solution, meaning every external wall in the house. That turns a small job into a big one more often than any other rule here, so check it before you plan around a single cold room.
The other rules are the same as every wall measure: the home must have been built and occupied before 31 December 2010, it needs its own MPRN, grant approval has to be in place before work starts, the work has to be done by a registered contractor, and a post-works BER is required before SEAI pays.
The rules every wall measure shares
- Built and occupied before 31 December 2010
- Its own MPRN
- Grant approval in place before work starts
- A registered contractor
- A post-works BER before SEAI pays
How it fits with the rest
If your cavity was filled and the fill has failed, internal insulation is one of the two routes open to you after the old fill comes out. If the outside of your house can be altered, external wall insulation is usually the better performer and leaves your rooms alone. And whichever wall measure you choose, attic insulation at 300mm is the cheaper first move and often what makes a larger wall job compliant.
No cost, no obligation
Get quotes for internal wall insulation
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.
Internal wall insulation questions
6 questions
Is internal wall insulation a good idea?
It's the right answer in two situations and a compromise in the rest. If your house is a protected structure or sits in a conservation area, external insulation may not be permitted and this is the grant-eligible alternative — SEAI names it as the option "when you don't have a cavity wall and external insulation is not possible (for protected structures)". It's also the sensible choice if you're already replastering and repainting, because the disruption is happening anyway. Outside those two, external insulation usually performs better and doesn't cost you floor area.
How much does internal wall insulation cost in Ireland?
SEAI publishes median costs from completed jobs: €8,600 on a detached house, €9,843 semi-detached or end of terrace, €9,804 mid-terrace and €5,736 for an apartment. Against grants of €4,500, €3,500, €2,000 and €1,500, that leaves you roughly €4,100 to €7,800 depending on the house. Half of jobs cost less than the median and half cost more, so use it to sanity-check a quote rather than to predict one.
How much room will I lose?
Roughly 60 to 100mm off each external wall, depending on the system and how much insulation the specification calls for. In a small bedroom with two external walls that's noticeable. In a large room it isn't. Worth measuring the rooms you care about before you decide, because this is the one drawback external insulation doesn't have.
How disruptive is it?
More than people expect. SEAI's own description is "quite disruptive and dusty". The rooms have to be cleared, and skirting boards, electrical sockets and anything fixed to the wall have to come off and go back. You end up with new plasterboard, a skim and fresh paint, so plan it for when you'd be redecorating anyway rather than as a standalone job.
Can I do one room at a time?
Not on a grant. SEAI requires a whole-surface solution: every external wall in the house has to be insulated for the wall grant to apply. You can do a room at a time and pay for it yourself, but the grant needs the whole job.
I already had cavity wall insulation. Can I get this grant?
Yes. SEAI allows a second wall insulation measure, and a previous cavity grant lets you apply for internal or external wall insulation. If the old cavity fill is wet or slumped it usually has to come out first — see cavity wall insulation removal.