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Do I need planning permission? Ireland's new exemptions from 27 July 2026

Last updated: · Figures checked 18 October 2026 · By the HouseWise team

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On 27 July 2026 seven new sets of exempted development regulations came into force (S.I. 338 to 344 of 2026). They raised the limits for rear extensions and garden structures and added new exemptions, including a small detached home in the back garden and subdividing a house into two units (Department circular PLR 02/2026, PDF; Citizens Information, edited 27 July 2026).

"Exempted development" means you don't need planning permission, as long as you meet every condition. Building and fire regulations still apply. If you're not sure, ask your local authority before you start: Citizens Information warns that building without permission you needed can lead to a large fine or even prison.

What changed on 27 July 2026

Work Before From 27 July 2026
Rear extension up to 40 m² up to 45 m² (including any earlier extensions)
Shed, garden room, home office or gym up to 25 m² up to 30 m²
Detached home in the back garden needed permission exempt, 32 to 45 m², with conditions
Subdividing your house into 2 units needed permission exempt, each unit at least 32 m², with conditions
Dormer to the side or back needed permission exempt, up to 30 m³
Rooflights at the front needed permission up to 2, each no bigger than 100 × 90 cm
External wall insulation needed permission exempt, up to 15 cm thick
Heat pump exempt at the rear no longer restricted to the rear
Bike or bin storage needed permission exempt, front or back, with size limits
Removing a chimney needed permission exempt, with conditions

Rear extensions (up to 45 m²)

  • The total added floor area (this extension plus any earlier ones, even ones that got permission) can't be more than 45 m².
  • Not higher than the house.
  • Above ground floor: at least 2 m from any boundary, and no more than 12 m² for a terraced or semi-detached house or 20 m² for a detached house.
  • You must keep at least 25 m² of private open space at the back.
  • There are more detailed rules about height, window positions and using the roof (for example as a balcony). Check them before you design.

Garden rooms, sheds and home offices (up to 30 m²)

  • At the back or side, not in front of the building line.
  • Up to 4 m high with a tiled or slated pitched roof, or 3 m with any other roof (most flat-roofed garden rooms).
  • 30 m² total, counting any other similar structures.
  • Keep at least 25 m² of open space at the back or side.
  • Finish to match the house.
  • Not lived in, and not used for commercial purposes (or to keep animals such as poultry or horses). Citizens Information lists a home office among the structures covered; if you plan to run a business from it, ask your council first.

More on costs in our garden room cost guide.

A detached home in the back garden (32 to 45 m²)

This is new and has the most conditions:

  • Built between 27 July 2026 and 31 December 2030.
  • 32 to 45 m², up to 4 m high (pitched tiled or slated roof) or 3 m (other roofs).
  • You own the main house and live in it as your main and only home.
  • It can't be sold or subdivided separately, and can't be used for short-term letting.
  • No separate utility connections (it shares the main house's services).
  • At least 0.6 m from any wall or boundary, and the main house keeps at least 25 m² of open space.
  • Notify your local authority at least 14 days before work starts.
  • It must meet building and fire regulations for a dwelling.
  • You can't use this exemption as well as the subdivision exemption.

Subdividing your home into two units

  • Done between 27 July 2026 and 31 December 2030.
  • Each unit at least 32 m², fully self-contained (only shared access).
  • Notify your local authority at least 14 days before starting.
  • Not combined with a detached garden home.

Dormers, rooflights, porches and other work

  • Dormers to the side or back: up to 30 m³ in total, not above the ridge, at least 20 cm from the roof edge. Front dormers still need permission.
  • Front rooflights: up to 2, each no bigger than 100 × 90 cm.
  • Porch: up to 2 m², more than 2 m from a public road or footpath; up to 4 m high (pitched tiled or slated) or 3 m (other roofs).
  • Garage conversion (attached, back or side) to domestic use: under 45 m².
  • External wall insulation: up to 15 cm, not projecting onto a public road, finished to match.
  • Solar panels on the roof of a house: exempt, and can cover the whole roof. See our solar panel grant guide.
  • Walls and fences: up to 1.2 m at the front and 2 m at the side or back. Widening or creating an access onto a public road always needs permission.

When the exemptions don't apply

  • Protected structures and homes in an architectural conservation area have extra restrictions.
  • A material change of use (for example, running a business from a converted garage) needs permission.

Ask your local authority if any of these might apply. You can also ask the council for a formal declaration on whether a specific project is exempt (a "Section 5 declaration").

FAQs

Can I build a 45 m² extension without planning permission? Yes, at the back of the house, if the total of all extensions is no more than 45 m², the house keeps at least 25 m² of rear open space, and you meet the other conditions.

Can my garden room be used as a bedroom? Not under the garden structure exemption, which rules out living in it. The separate detached garden home exemption (32 to 45 m²) allows a habitable home, with stricter conditions.

Can I rent out a garden home on Airbnb? No. Short-term letting is excluded, and it can't be sold separately from the main house.

Do I need planning permission for external wall insulation? Not since 27 July 2026, if it's no more than 15 cm thick and meets the other conditions. SEAI grants for external insulation are covered in our insulation grants guide.

Sources

All checked 18 October 2026.