House extensions in Kildare
In Kildare, building a house extension costs €1,800 to €2,500 per m² for one storey and €2,200 to €2,800 per m² for two, VAT included. With fees, a 20 m² ground-floor room comes to €48,000 to €60,000 and a 40 m² two-storey extension with an en-suite upstairs to €115,000 to €140,000. Behind the house, 45 m² can go on without a planning application if the conditions are met.
For homes in Naas, Newbridge, Maynooth, Celbridge, Leixlip, Kildare town and Athy: the cost of extending, the county's housing, its council, and the price of moving instead.
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- €1,800–€2,500per m², one storey in Kildare, VAT in
- €2,200–€2,800per m², two storeys
- 55%of Kildare houses have three bedrooms or fewer
- €435,000median paid by movers in Kildare, 2025
Extending a house in Kildare
Only 11% of Kildare houses have two bedrooms or fewer, the lowest share of any county in Ireland, and the average detached house has 3.8 bedrooms (Census 2022).
Moving up costs more here than anywhere outside Dublin and Wicklow. People moving home in Kildare paid a median of €435,000 in 2025, across 952 sales (CSO), so a move costs €12,000 to €23,000 in stamp duty, the agent's fee with VAT and the solicitor.
On the newer estates of Naas, Maynooth, Celbridge and Newbridge, read the planning permission for your estate before relying on the 45 m²: a condition in it can take the exemption away.
As a commuter county, Kildare is priced like Dublin: €1,800 to €2,500 per m² for one storey and €2,200 to €2,800 for two, VAT included. Planning applications go to Kildare County Council.
- 44%of houses have exactly three bedrooms
- 45%have four or more
- 3.3bedrooms in the average semi
- 74,504houses in Kildare (Census 2022)
What an extension costs in Kildare
| Extension | Per m² in Kildare, VAT in | Example, all in |
|---|---|---|
| One storey behind the house | €1,800–€2,500 | 20 m², mid-range: €48,000 to €60,000 |
| Ground-floor bedroom with an en-suite | €1,800–€2,500 | 16 m², standard finish: €38,000 to €53,000 |
| Two storeys, both floors counted | €2,200–€2,800 | 40 m² with an en-suite upstairs: €115,000 to €140,000 |
| Side extension | €2,000–€2,700 | 15 m², mid-range: €41,000 to €51,000 |
| Wraparound | €2,500–€3,500 | 40 m², mid-range: €125,000 to €150,000 |
| Mostly glass, or high spec | €3,000–€4,000 | 20 m² with a wall of glass: €65,000 to €90,000 |
| Garage conversion | One price for the job | €15,000–€45,000 |
Every example includes the build, the drawings and engineer's fees, any en-suite and VAT. Set aside 12% to 15% more for surprises.
Plan your house extension
Four quick taps, and your plan fills in as you answer: what it costs, whether it needs planning permission and how long it takes. Contact details come last, and only if you want a builder to price it.
25 m² single-storey rear in Kildare, mid-range finish: €59,000 to €73,000, including VAT and fees.
How the estimate is worked out
Every kind of extension has a build rate per m² for each region of Ireland, VAT at 13.5% included. A standard finish uses the lower half of that range and mid-range the upper half; high spec or a wall of glass moves the build to the glazed rate. Design, engineer and BER fees go on top, with anything you tick (an en-suite, a kitchen, a steel beam into the house) priced at your finish. A garage conversion gets one price for the whole job, since the walls and roof are already standing. Totals are rounded to the nearest €1,000. Use it to plan with. It isn't a quote: a builder prices your house after seeing it.
Extend or move in Kildare
On a €435,000 house, the median people moving home in Kildare paid in 2025, stamp duty on the next house is €4,350, the agent's fee on the sale €5,400 to €13,400 with VAT, and the solicitor €2,000 to €5,000. That is €12,000 to €23,000 spent before the bigger house's higher price, against €48,000 to €60,000 to build a 20 m² room here. Extend or move house has every county side by side.
Planning in Kildare
Planning rules don't change at the county line. Since 27 July 2026, 45 m² behind the house is exempt if it meets the conditions, and converting an attached garage shares that 45 m². Building at the side, and most two-storey extensions, need an application. In Kildare you apply to Kildare County Council: €34 for an extension, or €80 for a section 5 declaration on whether your plan is exempt.
Three things can take the exemption away. A condition in the planning permission your house was built under can remove it, and newer estates often have one. On a protected structure, work that would affect its character isn't exempt. And no extension is exempt if it would obstruct a public right of way or create a traffic hazard. Planning permission for a house extension.
Every way to extend a Kildare house
Each has its own page: costs by size, the planning rules that apply and the weeks of building.
Single-storey rearOne new room behind the house at ground level: a family room, a playroom or a bedroom for a parent.
Two-storeyTwo new floors in one build: more living space downstairs and an extra bedroom over it.
Side extensionThe strip beside a semi or detached house, built on at one level or two.
WraparoundAn L round the back corner of the house, for one big room with a utility or toilet off it.
Garage conversionThe garage you already have becomes a bedroom, an office or a playroom.
Bedroom and en-suiteOne more bedroom, downstairs or up, with a shower room of its own.House Extension coverage across every town in Co. Kildare
Click your town or Eircode routing key below to get a fast local price for your property in Co. Kildare.
Select your town, suburb or Eircode routing area in Co. Kildare below to pre-fill your location and open our quick 30-second quote check:
Local house extension coverage across Co. Kildare includes Naas & Sallins, Newbridge, Maynooth, Celbridge, Leixlip, Athy, Kildare Town, Clane & Prosperous, as well as Kilcock, Monasterevin, Kilcullen, Kill & Johnstown, Rathangan & Derrinturn, Castledermot, Athgarvan & Curragh and surrounding rural townlands.
Kildare questions
What does a house extension cost in Kildare?
In Kildare, building a house extension costs €1,800 to €2,500 per m² for one storey and €2,200 to €2,800 per m² for two, VAT included. With fees, a 20 m² ground-floor room comes to €48,000 to €60,000 and a 40 m² two-storey extension with an en-suite upstairs to €115,000 to €140,000. Behind the house, 45 m² can go on without a planning application if the conditions are met.
Does an extension in Kildare need planning permission?
Since 27 July 2026 you can build up to 45 m² behind the house without applying for planning permission. That 45 m² includes every extension added since 1964 and any attached garage you convert. The extension can't rise above the house, the house has to keep 25 m² of private open space, ground-floor windows need 1 m or more to the boundary they look onto, and no more than 12 m² of it can be upstairs on a semi or terrace (20 m² on a detached house). Before that date the limit was 40 m². Applications go to Kildare County Council.
Is it cheaper to extend or move in Kildare?
Moving on the Kildare median of €435,000 costs €12,000 to €23,000 in stamp duty, agent's and legal fees before the bigger house's price. A 20 m² room costs €48,000 to €60,000 to build here.
Which parts of Kildare do you cover?
All of it, including Naas, Newbridge, Maynooth, Celbridge, Leixlip, Kildare town and Athy. Your plan goes to a single vetted builder who works in Kildare.
Who will contact me?
One builder who works in Kildare and has been vetted, and only that one. They price the job in writing after seeing the house, and you decide.
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Room to grow, without moving
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