Cavity wall insulation in Dublin

Dublin homes and the 2010 cut-off

SEAI's wall grants are only for homes built and occupied before 31 December 2010. Census 2022 counted 519,023 households in Dublin. Of those, 8% were built in 2011 or later and fall outside the grant, and 48% were built before 1981, against 8% and 41% for the State (CSO).

CSO Census 2022 Small Area Population Statistics, county file, tables 6.1, 6.2, 6.3 and 6.5 (households). Read 29 October 2026. Percentages are of all households in the table, including those that didn't state an answer.

The four local authorities hold very different housing. Dublin City has 60% of its homes built before 1981 and 15% before 1919, with 38% of households in flats or apartments. Fingal is the opposite: 26% built before 1981, 12% built in 2011 or later, and 83% houses. South Dublin's biggest build decade was the 1970s, 23% of its homes, and Dún Laoghaire–Rathdown has 27% from 1961 to 1980 (CSO).

CSO Census 2022 Small Area Population Statistics, county file, tables 6.1, 6.2, 6.3 and 6.5 (households). Read 29 October 2026. Percentages are of all households in the table, including those that didn't state an answer.

What walls to expect

Not every Dublin house with a block outer wall has a cavity. Much of the housing built around Dublin in recent decades used single-leaf nine-inch hollow block, which one Irish building magazine describes as "notoriously difficult to insulate": with no continuous cavity, pump-filling isn't an option, and it notes that some Dublin companies have offered to pump-fill them anyway (Passive House Plus). SEAI's technical standards are clear that cavity hollow block walls are not suitable for cavity wall insulation (SEAI technical standards). For those homes the grant route is internal or external insulation: compare the three wall grants.

Older Dublin City housing adds a second question. 15% of Dublin City's homes were built before 1919, and homes of that age are often solid brick or stone, which the cavity grant doesn't cover: SEAI has a separate Traditional Homes pilot. A measured wall thickness and a look at the brick bond are the first clues.

The only way to know your own wall is a survey: a small drilled hole and a borescope on each elevation, which SEAI's standards require before any fill (SEAI technical standards). Is my house suitable? has the checks you can do yourself first.

How Dublin homes are heated

The grant doesn't depend on the fuel, but the fuel decides what an empty cavity costs you each winter. In Dublin, 66% of households heat with natural gas, 9% with oil and 17% with electricity (CSO).

CSO Census 2022 Small Area Population Statistics, county file, tables 6.1, 6.2, 6.3 and 6.5 (households). Read 29 October 2026. Percentages are of all households in the table, including those that didn't state an answer.

Gas is the Dublin fuel: 66% of households against 33% nationally, and oil only 9%. Dublin City also has the highest share of electric heating of the four counties, 23%, much of it in flats. An apartment with an unfilled cavity gets the €700 grant, but shared walls usually mean the management company has to agree before any wall is drilled.

Houses, flats, owners and renters

73% of Dublin households live in a house and 27% in a flat or apartment. 58% own their home, 24% rent privately and 10% rent from a local authority (CSO). The private rented share, 24%, is the highest of the four counties. A landlord with a HAP or RAS tenant gets the higher cavity rate, €1,700 for a semi-D, since 6 October 2026, and the grant's 2010 rule applies to the home, not the owner.

The grant and the cost in Dublin

SEAI pays a fixed amount by home type, not by county. SEAI's median costs are national too: €1,585 for a semi-D and €2,350 for a detached house from January to June 2026, so about €285 and €550 after the grant (SEAI's median costs PDF). SEAI doesn't publish a Dublin median, and we don't invent one. Get a written price with VAT stated and compare it with the national figure.

Costs: SEAI median costs, January to June 2026, from SEAI's median costs PDF (a sample of 23,412 completed upgrades; the cost each contractor submitted to SEAI at grant payment; VAT status not stated on the PDF), read 29 October 2026. Grants: Source: seai.ie wall insulation page, checked 29 October 2026.

Finding a registered installer in Dublin

Two lists, both national and both searchable: SEAI's register of contractors, which the grant requires, and NSAI's register of cavity wall insulation installers, which SEAI's technical standards require for the system being used. Check the company on both before you agree to anything. Or use the grant check on this page: we pass your request to one SEAI-registered contractor who covers Dublin.

Where these figures come from

• Housing figures are from the CSO's Census 2022 county file (DC, DR, FL, SD), read 29 October 2026. We add the local authorities together for the county figure.
• Grant amounts are from SEAI's wall insulation page, checked 29 October 2026. They are national.
• Costs are SEAI's national medians for January to June 2026. No county median exists, so none is given.
• Nothing on this page about local housing is estimated. If a local fact has no source, it isn't here.

Questions people ask