Will you need planning permission?

Pick a part of the garden, then measure it. The red outline is the largest size allowed without permission.

No planning permission needed

30 m² is within the limit (up to 45 m²), if the other conditions are met.

m²

Rear extension

No planning permission needed for a rear extension of up to 45 m², counting any earlier extensions built since 1 October 1964.

7 more conditions
  • Upstairs part: no more than 12 m² on a terraced or semi-detached house, 20 m² on a detached house.
  • Any upstairs part at least 2 m from a party boundary.
  • Walls no higher than the rear wall of the house (the side walls if the rear wall has a gable).
  • At least 25 m² of private open space must be left.
  • Windows at least 1 m from the boundary they face on the ground floor, 8 m upstairs.
  • The roof cannot be used as a balcony or terrace.
  • Only for the main house, not for a second house in the garden.

Before 27 July 2026 the limit was 40 m², and upstairs windows had to be 11 m from the boundary.

Class 1, S.I. No. 338 of 2026, in force since 27 July 2026; read 4 November 2026

Full guide: extension

Dormer (side or rear)

No planning permission needed for a dormer to the side or rear of the house if all dormers together have an inside volume of 30 m³ or less.

3 more conditions
  • No higher than the ridge of the roof.
  • Set back at least 20 cm from the eaves.
  • On the front roof: up to two roof lights, each no more than 100 cm long and 90 cm wide (Class 1C, same S.I.).

New class from 27 July 2026.

Class 1B, S.I. No. 344 of 2026, in force since 27 July 2026; read 4 November 2026

Full guide: dormer

Detached house in the back garden

A second, detached home in the back garden needs no planning permission if it has at least 32 m², stays within 45 m² together with sheds and similar structures, and is started and finished by 31 December 2030.

8 more conditions
  • Height: 4 m with a tiled or slated pitched roof, 3 m otherwise.
  • At least 0.6 m from any wall or boundary; windows at least 0.6 m from the boundary they face.
  • At least 25 m² of private open space must be left.
  • No separate connection to water, wastewater or other utilities; no new access onto the road.
  • It cannot be sold separately, subdivided or used for short-term letting.
  • The main house must be the owner's home when work starts.
  • Tell the council at least 14 days before work starts, with the Eircode.
  • Not allowed if the house has been subdivided.

New class from 27 July 2026, until 31 December 2030.

Class 3A, S.I. No. 340 of 2026, in force since 27 July 2026; read 4 November 2026

Full guide: garden house

Shed, garage or log cabin

Sheds, garages, greenhouses, stores and similar structures need no planning permission up to 30 m² in total, as long as they are behind the front wall of the house.

4 more conditions
  • Height: 4 m with a tiled or slated pitched roof, 3 m otherwise.
  • At least 25 m² of private open space must be left to the rear or side.
  • At the side of the house, finishes and roof must match the house.
  • Not for living in: a log cabin counts here only if nobody lives in it (no human habitation).

Before 27 July 2026 the limit was 25 m².

Class 3, S.I. No. 338 of 2026, in force since 27 July 2026; read 4 November 2026

Full guide: shed or cabin

Heat pump

An air-source or ground heat pump needs no planning permission if all heat pumps together cover 2.5 m² or less.

4 more conditions
  • At least 50 cm from any edge of the wall or roof it is fixed to.
  • It must not stick out onto a public road.
  • Noise: no more than 43 dB(A), or 5 dB(A) above background noise if that is higher, measured at the nearest neighbouring home.
  • Ground level not raised or lowered by more than 1 m.

Before 27 July 2026 a heat pump could not go on, or forward of, the front wall or roof.

Class 2(d), S.I. No. 342 of 2026, in force since 27 July 2026; read 4 November 2026

Full guide: heat pump

Bike or bin store

A bike or bin store needs no planning permission if it is no bigger than 3.5 m² and no higher than 1.4 m.

2 more conditions
  • In the front garden: at least 0.6 m away from the front wall of the house.
  • In the front garden: it must not take away more than half of the open part of the garden.

New class from 27 July 2026.

Class 62, S.I. No. 341 of 2026, in force since 27 July 2026; read 4 November 2026

Full guide: bike or bin store

External wall insulation

Insulation on the outside walls needs no planning permission if it is no thicker than 150 mm on the front, rear or gable walls.

2 more conditions
  • It must not stick out onto a public road.
  • It must not change the look of the house so much that it no longer fits the house and its neighbours.

New class from 27 July 2026.

Class 63, S.I. No. 341 of 2026, in force since 27 July 2026; read 4 November 2026

Full guide: wall insulation

Removing a chimney

You can take down a chimney without planning permission, unless it is part of a joint stack with a separate house.

2 more conditions
  • The roof must be finished the same as the existing roof.
  • Nests of wild birds and resting places of bats are protected (sections 22 and 23 of the Wildlife Act 1976).

New class from 27 July 2026.

Class 2A, S.I. No. 343 of 2026, in force since 27 July 2026; read 4 November 2026

Full guide: chimney

Dividing the house in two

You can divide a house into two homes without planning permission if each has at least 32 m² and the work is started and finished by 31 December 2030.

5 more conditions
  • No more than two homes in total.
  • Each home self-contained, sharing only the way in.
  • Tell the council at least 14 days before work starts, with the Eircode.
  • Not allowed if a detached house has been built in the back garden.
  • Building Regulations, including fire safety, still apply.

New class from 27 July 2026, until 31 December 2030.

Class 1A, S.I. No. 339 of 2026, in force since 27 July 2026; read 4 November 2026

Full guide: two homes

Everything in the garden, and its limit

An exemption does not apply in some cases, for example if the work would break a condition of an earlier planning permission or extend an unauthorised structure (article 9 of the Planning and Development Regulations 2001). S.I. No. 600 of 2001

Over the limit? Your odds, council by council

Share of planning applications granted and median wait for a decision, 3 November 2025 to 3 November 2026. Councils most likely to say yes come first. The dot shows the wait, from 45 days on the left to 105 on the right.

  1. Cavan 96% granted about 1 in 23 refused 62 days
  2. Tipperary 95% granted about 1 in 22 refused 56 days
  3. Leitrim 95% granted about 1 in 19 refused 53 days
  4. Clare 95% granted about 1 in 19 refused 54 days
  5. Kilkenny 94% granted about 1 in 17 refused 63 days
  6. Mayo 94% granted about 1 in 17 refused 59 days
  7. Donegal 93% granted about 1 in 15 refused 51 days
  8. Cork County 93% granted about 1 in 14 refused 66 days
  9. Monaghan 93% granted about 1 in 14 refused 100 days
  10. Laois 93% granted about 1 in 14 refused 55 days
  11. Sligo 92% granted about 1 in 13 refused 53 days
  12. Waterford 91% granted about 1 in 12 refused 55 days
  13. South Dublin 91% granted about 1 in 11 refused 55 days
  14. Offaly 91% granted about 1 in 11 refused 64 days
  15. Dublin City 91% granted about 1 in 11 refused 55 days records stop 30 July 2026
  16. Carlow 90% granted about 1 in 10 refused 63 days
  17. Dún Laoghaire-Rathdown 90% granted about 1 in 10 refused 53 days
  18. Kerry 89% granted about 1 in 9 refused 64 days
  19. Limerick 89% granted about 1 in 9 refused 55 days
  20. Wicklow 89% granted about 1 in 9 refused 53 days
  21. Louth 87% granted about 1 in 7 refused 51 days
  22. Galway City 86% granted about 1 in 7 refused 55 days
  23. Roscommon 85% granted about 1 in 7 refused 99 days
  24. Westmeath 85% granted about 1 in 7 refused 55 days
  25. Galway County 84% granted about 1 in 6 refused 55 days
  26. Meath 84% granted about 1 in 6 refused 55 days
  27. Longford 84% granted about 1 in 6 refused 49 days
  28. Wexford 83% granted about 1 in 6 refused 54 days
  29. Kildare 81% granted about 1 in 5 refused 62 days
  30. Fingal 78% granted about 1 in 5 refused 54 days records stop 8 September 2026
  31. Cork Citydata missingno decision recorded in these 12 months; last application received 4 November 2025
The same figures as a table
Planning decisions by council, 3 November 2025 to 3 November 2026
CouncilGrantedMedian waitAsked for more informationDecisions recorded
Carlow90%63 days47%346
Cavan96%62 days48%583
Clare95%54 days27%1038
Cork County93%66 daysnot recorded2482
Donegal93%51 days29%2026
Dublin City91%55 days20%2332
register stops 30 July 2026
Dún Laoghaire-Rathdown90%53 days14%2050
Fingal78%54 days19%1517
register stops 8 September 2026
Galway City86%55 days25%320
Galway County84%55 days32%1812
Kerry89%64 days46%1158
Kildare81%62 days45%1086
Kilkenny94%63 days47%786
Laois93%55 days39%584
Leitrim95%53 days38%228
Limerick89%55 days40%1287
Longford84%49 days36%280
Louth87%51 days40%819
Mayo94%59 days40%1158
Meath84%55 days36%1344
Monaghan93%100 days66%501
Offaly91%64 days49%488
Roscommon85%99 days57%468
Sligo92%53 days29%432
South Dublin91%55 days24%1148
Tipperary95%56 days39%1085
Waterford91%55 days38%775
Westmeath85%55 days39%518
Wexford83%54 days36%1454
Wicklow89%53 days40%1073
Cork CityData missing: no decision recorded in these 12 months; last application received 4 November 2025

How the odds are worked out

The odds come from the national register of planning applications, which each council fills in. For each council we count the decisions made between 3 November 2025 and 3 November 2026: 31,178 in all. "Granted" is the share of grants among grants and refusals. Invalid and withdrawn applications are left out. The median wait is the number of days from application to decision that half of the grants and refusals beat.

A council whose records stop early is marked on the list, and a council with no recent decision shows "data missing" rather than a zero.