Dublin City
27.7% of homes built before 1945, 24 conservation areas. Rathmines, Ranelagh and around.
Dun Laoghaire-Rathdown is two housing markets in one county. 12.1% of its homes predate 1945 — the Victorian and Edwardian terraces along the coast through Monkstown, Dalkey and Dun Laoghaire itself — while well over half went up after 1960 in the inland suburbs. Which half your house sits in decides the measure.
It also carries more conservation designation than anywhere else in Dublin, including eight areas that are proposed rather than in force.
The coastal strip is the old part. Those are solid-walled houses in most cases, so there is no cavity to fill and the wall options are the expensive ones. Several of those terraces sit inside conservation areas that cover the whole street.
Inland is a different county. Stillorgan, Sandyford, Dundrum, Cabinteely and the Leopardstown side are largely 1960s to 2000s housing — 13.3% of the county went up in the 1960s alone and another 13.2% in the 1970s — and housing of that age generally has a cavity.
So the county average tells you very little here. A house in Monkstown and a house in Sandyford need different measures, different budgets and different planning conversations, and they're eight kilometres apart.
The census records when a home was built, not what its walls are made of. Age is a good proxy; the actual test is a borescope through one drilled hole.
| Built | Homes | Share |
|---|---|---|
| Pre 1919 | 5,347 | 6.3% |
| 1919 - 1945 | 4,986 | 5.9% |
| 1946 - 1960 | 10,915 | 12.8% |
| 1961 - 1970 | 11,328 | 13.3% |
| 1971 - 1980 | 11,232 | 13.2% |
| 1981 - 1990 | 9,844 | 11.6% |
| 1991 - 2000 | 8,877 | 10.4% |
| 2001 - 2010 * | 13,486 | 15.8% |
| 2011 - 2015 | 2,505 | 2.9% |
| 2016 or later | 5,573 | 6.5% |
* the largest single group. Percentages are of 85,110 households, and exclude the small number the census records as "not stated".
Only external wall insulation raises this, and only where a home is a protected structure or sits inside an Architectural Conservation Area. Each local authority designates its own in its own development plan, and the four Dublin authorities have drawn them very differently.
Dún Laoghaire-Rathdown County Council lists 37 conservation areas in the Dún Laoghaire-Rathdown County Development Plan 2022–2028. They cover entire suburbs in several cases, not just village cores. Of those, 29 are designated and 8 are candidates — proposed but not yet in force. A candidate area can become live during the life of a project, so ask about both.
Dun Laoghaire-Rathdown designates more areas than any other Dublin authority, and several of them cover an entire suburb rather than a terrace or a village core.
Ask about your specific address. These boundaries run down the middle of streets and two neighbours can get different answers.
37 listed by Dún Laoghaire-Rathdown County Council in the Dún Laoghaire-Rathdown County Development Plan 2022–2028
Among them, each covering a whole residential area:
The full list and the maps are published by the council. Start at Dún Laoghaire-Rathdown County Council.
On the coastal side, expect external or internal wall insulation and expect the planning question to be real. On the inland side, expect cavity wall insulation, which costs a fraction of either and is usually done within a day.
If your cavity was filled years ago and the room is damper or colder than it used to be, the fill may have to come out before anything else happens. That job has its own page.
Grant amounts are national and do not vary by address. Read from seai.ie, checked 15 August 2026.
What a semi-detached home pays after the grant, at SEAI's median installed cost. Both apply here, and which one is yours depends on whether you are on the coastal side or the inland side.
27.7% of homes built before 1945, 24 conservation areas. Rathmines, Ranelagh and around.
3.7% of homes built before 1945, 27 conservation areas. Swords, Blanchardstown and around.
2.3% of homes built before 1945, 18 conservation areas. Tallaght, Clondalkin and around.
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Dun Laoghaire-Rathdown designates more areas than any other Dublin authority, and several of them cover an entire suburb rather than a terrace or a village core. Dún Laoghaire-Rathdown County Council lists 37 conservation areas in the Dún Laoghaire-Rathdown County Development Plan 2022–2028, covering entire suburbs in several cases, not just village cores. Ask about your specific address rather than your area.
On the coastal side, expect external or internal wall insulation and expect the planning question to be real. On the inland side, expect cavity wall insulation, which costs a fraction of either and is usually done within a day. The largest single group of homes here, 15.8% of the total, was built in 2001 - 2010. A borescope through one drilled hole settles what your own wall is.
SEAI requires the home built and occupied before 31 December 2010, with its own MPRN. 89.3% of homes in Dún Laoghaire-Rathdown clear that — 76,015 of 85,110 households. The 9.5% built since do not, and they went up to a considerably better standard to begin with.
2001 - 2010, which accounts for 15.8% of its housing and is the single largest group. The coastal strip is the old part. Those are solid-walled houses in most cases, so there is no cavity to fill and the wall options are the expensive ones. Several of those terraces sit inside conservation areas that cover the whole street.
No. SEAI sets amounts by measure and dwelling type, not by address — €6,000 on a semi-detached external wall job anywhere in the country. What changes locally is which measure your house can take. If your cavity was filled years ago and the room is damper or colder than it used to be, the fill may have to come out before anything else happens. That job has its own page.