Dublin · checked 29 October 2026
Underpinning in Dublin
Dublin City has the highest share of pre-1919 homes of any council area on this site, and Co. Dublin is one of two places Geological Survey Ireland has mapped for ground instability. What that means for a house with cracks, and who to call.
Facts on this page checked against each source on 29 October 2026. Each one links to its source. How we check
In Census 2022, 34.5% of the 518,490 households in Dublin lived in homes built before 1971, against 28.5% nationally, and 8.1% in homes built before 1919 (CSO).
Underpinning here works the way it does everywhere: a chartered structural engineer first, then the cause, then the design. This page adds what is particular to Dublin: the age of its houses, its ground, and the schemes that apply.
The age of the housing in Dublin
| Area | Households | Pre-1919 | Pre-1971 | Pre-1991 | 1991 to 2010 |
|---|---|---|---|---|---|
| Dublin | 518,490 | 8.1% | 34.5% | 57.8% | 31.5% |
| Dublin City | 225,519 | 14.9% | 51.5% | 66.9% | 24.3% |
| Dún Laoghaire-Rathdown | 85,110 | 6.3% | 38.3% | 63.0% | 26.3% |
| Fingal | 107,599 | 2.1% | 11.4% | 37.7% | 47.9% |
| South Dublin | 100,262 | 0.9% | 17.9% | 54.4% | 34.7% |
| Ireland | 1,836,728 | 8.4% | 28.5% | 50.8% | 39.1% |
Source: CSO Census 2022, table SAP2022T6T2CTY, permanent private households by year built. Shares are of all households, including those whose year built wasn't stated.
Why age matters: civil engineer Kieran McCarthy says most Irish suburbs built in the early 1970s or before will likely have clay drains, and that leaking drains cause most of the subsidence he sees (Irish Examiner, 2021). And the national Building Regulations, including requirement A2 that foundations cope with ground movement, apply to buildings from 1 June 1992 on (TGD A). In Dublin, 57.8% of households live in homes built before 1991.
Ground conditions in Dublin
- Geological Survey Ireland's PanGeo study mapped nine areas of potential or observed ground instability in Co. Dublin, about 33.51 km² in all, which is under 4% of the county. The main observed instability is compressible ground. The largest area of potential instability is the peat of the Dublin Mountains (PanGeo geohazard description for Dublin).
- Around the port, part of the Liffey estuary is made ground, and satellite radar picked up subsidence in parts of a 3 km stretch. GSI describes made ground as anything from engineered fill to material that can contain voids, compressible material, or material that can decompose, dissolve or expand (PanGeo Dublin).
- After the last glaciation, rivers, lakes and people laid down soft, compressible ground across the county: alluvium in river channels, estuarine silts and clays, and reclaimed land (PanGeo Dublin).
- Outside the city the land is mostly lowland limestone glacial till. Along the western county boundary, from Balbriggan to Newcastle, heavy glacial till gives poorly drained surface-water gley soils (Farmers Journal soil survey of Co. Dublin).
These notes describe the county's soils and geology in general. They are background for a conversation with an engineer, never a verdict on one house.
A Dublin example, with figures
In 2020 The Irish Times looked at a semi-detached house in Rathgar, Dublin 6, bought in 2018 knowing it had subsidence and needed underpinning. A structural engineer costed piling under it at €16,000, at trade rates he estimated were about 20% below what most buyers would pay, with piles going down 6 metres. He put a ground investigation at around €3,000 (The Irish Times, 24 April 2020). Those are 2020 figures for one house, not a price list.
Pyrite and defective blocks in Dublin
Pyrite Remediation Scheme: all four Dublin council areas are in the scheme. As published in 2020, homes had to be built and completed between 1 January 1997 and 12 December 2013, certified with a damage condition rating of 2 attributable to pyrite heave, and meet the scheme's other conditions (C&AG). Pyrite heave lifts floors; underpinning doesn't fix it.
See pyrite and defective blocks.
Getting a house in Dublin looked at
- Record the cracks.Dated photos, inside and out, with a ruler in the shot. Don't fill them yet.
- Get a chartered structural engineer.The engineer grades the cracks, finds the cause and decides whether underpinning is needed at all. Engineers Ireland awards the CEng MIEI title (Engineers Ireland).
- Check the drains.A CCTV drain survey shows whether old drains are leaking, the usual cause.
- Tell your insurer if you're claiming.As soon as reasonably possible. See the insurance guide.
- Get the design priced.Send your details and one experienced groundworks and underpinning contractor who covers your county rings you to talk it through.
The full order of work is on the underpinning process page, and the methods on underpinning methods.
Nearby counties
County Meath · County Kildare · County Wicklow · County Louth · All county pages
Questions people ask
Is there a subsidence map for Dublin?
Geological Survey Ireland's PanGeo study maps areas of potential or observed ground instability in Co. Dublin, with a report for each area. GSI says the maps are broadly indicative and not for site-specific use. An engineer's assessment is what tells you about your own house.
Does the pyrite scheme cover Dublin?
Yes, for all four Dublin council areas: Dublin City, Dún Laoghaire-Rathdown, Fingal and South Dublin, for homes that meet the scheme's conditions. Pyrite heave lifts floors; it is a different problem from foundations sinking.
How old are Dublin's homes?
In Census 2022, 34.5% of Dublin's 518,490 households lived in homes built before 1971. In Dublin City Council's area it was 51.5%.
Who will ring me?
We pass your request to one experienced groundworks and underpinning contractor who covers your county. Your number isn't sent to a list. They ring you, ask what's happening and about any engineer's report, and price the work from the engineer's design. Nothing is booked until you say yes.
Cracks in a house in Dublin?
Five quick questions and one experienced groundworks and underpinning contractor who covers your county rings you. Or call 087 162 1846 between 8am and 8pm.