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What can I build without planning permission in Ireland?

A defined list of small domestic works — rear extensions up to 40 m², rear sheds and garages up to 25 m² combined, boundary walls and fences within height limits, and other categories set out in Schedule 2 to the Planning and Development Regulations 2001 — are exempted development if every condition in the relevant class is met.

Irish planning law does not require permission for every piece of building work. Schedule 2 to the Planning and Development Regulations 2001 (as amended) sets out a series of numbered classes of "exempted development" — categories of work that are deemed to already have permission because they are considered minor enough not to need it, provided every condition attached to that class is satisfied.

The best-known examples for houses are: a rear extension up to 40 m² (Class 1), a shed or similar rear structure up to 25 m² (Class 2), a garage or carport within the same 25 m² allowance (Class 3), boundary walls and fences up to set height limits (Class 9), and works such as replacement windows, driveways, solar panels and small domestic renewable-energy installations, each covered by its own class with its own conditions.

None of these exemptions apply automatically to every house. They can be restricted or removed entirely if the property is a protected structure, sits in an architectural conservation area, is in a special planning control area, or is subject to a condition in an earlier grant of permission that expressly removes exempted development rights. Works that materially affect the character of a protected structure are never exempted.

Common categories of exempted development

The most frequently used classes for ordinary houses include:

  • Class 1 — rear extensions up to 40 m² (with a smaller allowance above ground-floor level)
  • Class 2 — sheds, greenhouses and similar structures to the rear, up to 25 m² combined
  • Class 3 — garages, carports and stores to the rear or side, within the same 25 m² allowance
  • Class 4 — certain works to the external finish of a house
  • Class 6 — certain hard-surfacing of a domestic driveway
  • Class 9 — boundary walls, gates and fences within height limits
  • Class 50-51 — solar panels and other micro-renewable energy installations, subject to size and location limits

Each class has its own precise wording, and the conditions matter as much as the headline size limit — always check the specific class before assuming an exemption applies.

When to get a formal answer

If you are unsure whether proposed works fall within an exempted development class, you can apply to your local planning authority for a section 5 declaration under the Planning and Development Act 2000. This gives a binding written determination on whether specific works are or are not exempted development, and it is the safest route before starting anything borderline or before selling a property with unauthorised-looking works.

Sources

Last reviewed 20 August 2026. General information only — not legal or planning advice.

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