By Quick answer: Yes. Since 27 July 2026, homeowners in Ireland can build a detached “granny flat” of 32 to 45 square metres in the rear garden without planning permission, under the new Class 3A exemption. You must notify your local authority at least 14 days before starting, meet Building Regulations, and satisfy a list of conditions. There is no separate “NOC” to obtain.
What changed on 27 July 2026?
The Planning and Development (Exempted Development) Regulations 2026 came into effect on Monday 27 July 2026. They are the biggest expansion of residential planning exemptions in years. The headline change is Class 3A, which allows a Detached Auxiliary Dwelling (DAD), a small permanent home in the rear garden of a principal house, without a planning application.
Before July 2026, garden structures under Class 3 were limited to non-habitable uses such as sheds, offices and gyms. Class 3A is the first exemption for a detached home in the garden.
What are the Class 3A rules at a glance?
| Requirement | Detail |
|---|---|
| Floor area | 32 m² minimum, 45 m² maximum |
| Location | Rear garden of the principal house |
| Height | Up to 4 metres with a tiled or slated pitched roof (a separate limit applies to other roof types, so check the council form) |
| Boundary | At least 0.6 metres from the boundary the structure faces |
| Garden left | Private open space for the main house must not fall below 25 m² |
| Occupation | Only in conjunction with the main house; cannot be sold or subdivided separately |
| Letting | Cannot be used for short-term letting |
| Main residence | The principal house must be the owner’s sole or main residence when work starts |
| Access | No new vehicular or pedestrian access onto a road; independent pedestrian or wheelchair access within the site |
| Deadline | Must be completed by 31 December 2030 |
Councils including Dublin City, Cork City, Fingal and Wicklow have published notification forms listing these conditions. Always check the exact wording on your own council’s form, because the full statutory text (S.I. 339 and S.I. 340 of 2026) governs.
Do I need a “NOC” or any permission from the council?
Ireland’s planning system does not use a “No Objection Certificate”. Under Class 3A you do not apply for permission. You notify the planning authority in writing at least 14 days before commencement, giving the property location and Eircode and the reason you are using the exemption. Building Control rules, including fire safety, still apply in full.
What still applies even without planning permission?
- Building Regulations and fire safety: the unit must meet standards for a habitable dwelling.
- Services: it must connect to the principal house’s services, so check water, wastewater and electricity capacity.
- Existing planning conditions: restrictive conditions attached to your house’s original permission can still bind you.
- Designations: protected structures and other special designations can affect whether an exemption is available. Ask your council if unsure.
Who is a Class 3A granny flat for?
The Government framed the change around family: an older relative, an adult child, or a carer. Because letting is limited and the unit cannot be sold separately, it is not a route to a new rental business or a separate house on a site.
Can I build more than one?
No. Class 1A (subdividing the main house) is not available where a detached house has been built in the rear garden under Class 3A. The two exemptions are alternatives, not a bundle. See our guide to Class 1A.
Key takeaways
- 32 to 45 m², rear garden, permanent, notification required 14 days ahead.
- No NOC and no planning application, but Building Regulations still apply.
- Family use only; no short-term letting or separate sale.
- Complete by 31 December 2030.
FAQs
Can I build a granny flat in Ireland without planning permission in 2026?
Yes, if it meets every Class 3A condition: 32 to 45 m², in the rear garden, linked to the main house’s services, built to Building Regulations, and notified to your council at least 14 days before work begins.
How big can an exempt granny flat be in Ireland?
Between 32 and 45 square metres of floor area. Any other Class 3 garden structures already on the site count towards the 45 m² total.
Is there a deadline to use the Class 3A exemption?
Yes. The development must be started and completed by 31 December 2030.
Can I rent out a Class 3A granny flat?
It must be occupied in conjunction with the main house and cannot be used for short-term letting. Check your council’s guidance before any long-term letting arrangement.
Does a granny flat need Building Regulations approval?
Yes. It must comply with Building Regulations, including fire safety, and Building Control requirements for a habitable dwelling.
This article is general information, not legal or planning advice. Confirm details with your local authority.
Sources: Fieldfisher, “New Exempted Development Regulations 2026”; MyHome, “New planning regulations come into effect on Monday” (24 July 2026); Cork City Council exemption page; Dublin City Council and Laois, Limerick, Waterford, Galway and Wicklow council Class 3A notification forms (July to September 2026).
