Where the exemptions are
- Section 4 of the Act lists some exemptions directly, such as certain works by local authorities and works that only affect a building's interior.
- Schedule 2 of the Regulations lists classes of exempted development, each with conditions and limits: for example, extensions to the rear of a house up to a set floor area, sheds and garages within the curtilage, boundary walls up to a set height, and certain agricultural buildings.
The limits are detailed (floor areas, heights, distances from boundaries, how much garden must remain) and they do change. The two most-used classes were last changed on 27 July 2026, and the figures below are the current ones.
Do I need planning permission for a shed or garden room?
Usually not, if it meets every condition of Class 3. This covers sheds, garages, greenhouses, stores, garden offices and home gyms within the curtilage of a house:
- Not in front of the front wall of the house.
- All such structures together no more than 30 m² (it was 25 m² before 27 July 2026), counting any already there.
- At least 25 m² of private garden must remain to the rear or side of the house.
- No higher than 4 m with a tiled or slated pitched roof, or 3 m otherwise.
- To the side of the house, the finishes and roof must match the house.
- Not lived in, and used only for purposes incidental to the house: no keeping pigs, poultry, pigeons, ponies or horses.
A garden room you'd sleep in is a different matter. The 2026 changes also brought in a separate exemption for a detached auxiliary dwelling of 32 m² to 45 m² in the back garden, linked to the main house's services, with its own conditions. Building Regulations apply to it as to any home.
Do I need planning permission for an extension?
A rear extension is exempt under Class 1 if, among other conditions:
- Its floor area, added to any extension built since 1 October 1964, is no more than 45 m² (40 m² before 27 July 2026).
- Any part above ground floor is no more than 12 m² for a terraced or semi-detached house, or 20 m² for a detached house, and at least 2 m from any party boundary.
- At least 25 m² of private garden remains behind the house.
- It's no higher than the house's rear wall (or side walls, if the rear is a gable), and the roof isn't used as a balcony.
- Ground-floor windows are at least 1 m from the boundary they face; upstairs windows at least 11 m.
Other common exemptions
The Regulations also cover boundary walls and fences, porches, heat pumps, solar panels, external insulation, and bike and bin storage. Since 27 July 2026 there are new exemptions for dormer roof extensions and for dividing a house into two self-contained homes of at least 32 m² each. Check the conditions of the class that fits before you build.
When the exemption doesn't apply
Article 9 of the Regulations takes away exempted status in certain situations, including where the works would:
- materially affect the character of a protected structure, or of an Architectural Conservation Area, for many types of works;
- need Appropriate Assessment because they could affect a European site;
- create a traffic hazard, or form or widen an access to a public road beyond set limits;
- contravene a condition of an existing planning permission;
- interfere with a recorded archaeological monument or certain protected views and amenities.
Section 5 declarations
Under section 5 of the Act, anyone can ask the council for a declaration on whether something is development, and whether it's exempted development. You give details and drawings of the works and pay a fee. The decision can be referred to An Coimisiún Pleanála for review.
Section 57 declarations (protected structures)
The owner or occupier of a protected structure can ask the council for a declaration under section 57 setting out which works would or wouldn't materially affect its character, and so which would need permission.
Sources
- Planning and Development Act 2000, sections 4, 5 and 57
- Planning and Development Regulations 2001 (as amended), Article 9 and Schedule 2
- Planning and Development (Exempted Development (Act of 2000)) Regulations 2026 (S.I. No. 338 of 2026), in force 27 July 2026: Classes 1 and 3
- Department of Housing, Local Government and Heritage, New Planning Exemptions Regulations come into effect today, 27 July 2026
Last reviewed 2026-10-07.