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Do I need planning permission for a conservatory in Ireland?

A conservatory is treated as an extension, so it can be exempted development under Class 1 of Schedule 2 to the Planning and Development Regulations 2001 if it is built to the rear, stays within the 40 m² cumulative limit and meets the other conditions in that class; front or oversized conservatories need permission.

There is no separate planning class for a conservatory — it is assessed under Class 1 of Schedule 2 to the Planning and Development Regulations 2001 in the same way as any other rear extension, whatever its glazing or construction method.

That means a conservatory to the rear of the house qualifies for exemption only if its floor area, added to any other extension built since 1 October 1964, does not exceed 40 m², and if the reduced allowance for anything above ground-floor level, the height limit, and the requirement to retain at least 25 m² of private open space are all met.

A conservatory built to the front or side of a house, one that pushes the cumulative extension total over 40 m², or one on a protected structure will not be exempted development, and full planning permission will be required before construction.

Points to confirm before building

Treat the conservatory exactly like a rear extension and check:

  • It is built to the rear of the house, not the front or side
  • Combined extension floor area (including this conservatory) is 40 m² or less
  • Height does not exceed that of the existing house
  • At least 25 m² of private open space remains after construction
  • No earlier planning condition has removed exempted development rights
  • The house is not a protected structure or in a conservation area

A fully glazed structure still needs to comply with Building Regulations, including thermal performance requirements that can be more demanding for conservatories than for a standard block-built extension.

Getting it confirmed

Because glazed conservatories are often added on top of an existing extension, check the property's full planning history before assuming the 40 m² allowance is still available, and apply for a section 5 declaration if there is any doubt.

Sources

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

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