Do I Need Planning Permission?
Most development in Ireland needs planning permission, but many common home projects are exempt: a rear extension up to 45 sq m, a shed or garden room up to 30 sq m, rooftop solar with no area limit, and a front wall up to 1.2 m. Every exemption carries conditions, and none apply to a protected structure or in an Architectural Conservation Area.
Answer a few questions about your project below for a plain-English answer with the exact regulation cited.
What type of development are you planning?
Exemption thresholds at a glance
Current limits under the Planning and Development Regulations 2001, as amended by S.I. 338 to 344 of 2026 on 27 July 2026:
| Project | Limit | Key condition |
|---|---|---|
| Rear extension | 45 sq m | Cumulative with every previous extension. Must leave 25 sq m of private open space |
| Garden shed, room, office or gym | 30 sq m | Total of all outbuildings. No sleeping accommodation |
| Habitable garden cabin (Class 3A) | 32 sq m min | Capped at 45 sq m combined with other garden structures. 14 days notice to the council |
| Rooftop solar on a house | No limit | Since October 2022. Placement conditions apply |
| Front boundary wall or fence | 1.2 m | 2 m at the side or rear |
| Porch | 2 sq m | At least 2 m back from the public road |
No exemption applies to a protected structure or a property in an Architectural Conservation Area. For the full list and the conditions attached to each, see the exempted development guide.
Frequently asked questions
What can I build without planning permission in Ireland?
The main exemptions are a rear extension up to 45 square metres, garden structures such as a shed, home office or gym up to 30 square metres, a habitable garden cabin of 32 to 45 square metres under the new Class 3A rules, rooftop solar panels with no area limit, boundary walls up to 1.2 metres at the front and 2 metres at the side or rear, a porch up to 2 square metres, and internal alterations. Every one carries conditions, and none apply to a protected structure or in an Architectural Conservation Area.
What happens if I build without planning permission?
Unauthorised development is an offence under the Planning and Development Act 2000. The council can serve an enforcement notice requiring you to undo the work, and District Court fines run to €5,000. Enforcement is generally time-barred after 7 years, but the development stays unauthorised, which surfaces in the solicitor's searches when you sell and can block a mortgage or an insurance claim.
How do I get a definite answer on whether I need permission?
Apply to your local authority for a Section 5 Declaration. It costs about €80, the council must decide within 4 weeks, and the answer is legally binding. It is worth doing whenever a project is close to a threshold, because the cost of being wrong is an enforcement notice.
Did the exemption rules change in 2026?
Yes. S.I. 338 to 344 of 2026 came into operation on 27 July 2026 and made the biggest change to household exemptions in decades: extensions rose from 40 to 45 square metres, garden structures from 25 to 30 square metres, and a new Class 3A allows a habitable garden dwelling. Much of the advice published online still quotes the old figures.
