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Do I need planning permission for a garden room in Ireland?

It depends on how it is used. A garden room used for domestic purposes such as a home office, gym or study can fall within the 25 m² rear-structure exemption in Class 2 of Schedule 2 to the Planning and Development Regulations 2001, but a garden room used as sleeping or living accommodation is not exempted development.

The regulations do not use the term “garden room”. A garden room is assessed as a structure within the curtilage of a house, so the same Class 2 conditions that apply to sheds and garden stores apply here: rear of the house, 25 m² combined floor area, height limits and at least 25 m² of retained private open space.

The condition that usually decides the question is use. Class 2 excludes structures used for human habitation, so a garden room fitted out as a bedroom, a granny flat or a self-contained unit falls outside the exemption and needs planning permission.

Renting the room out, running a business with customer visits, or installing services that create a separate dwelling can also amount to a material change of use requiring permission.

Points to confirm before ordering

A garden room is more likely to be exempt where:

  • It sits to the rear, not forward of the front wall of the house
  • Its floor area, with other Class 2 structures, is 25 m² or less
  • Height stays within the Class 2 limits for the roof type
  • At least 25 m² of private open space remains
  • It is used for domestic purposes ancillary to the house
  • It contains no sleeping accommodation and is not a separate dwelling

Note that exempted development status says nothing about Building Regulations compliance, which is a separate matter.

When to check

If the room will include a bedroom or shower, if you intend to let it, or if the property is a protected structure or in an architectural conservation area, contact your local planning authority or apply for a section 5 declaration before committing.

Sources

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

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