Do You Need Planning Permission for a Log Cabin in Ireland?

Since 27 July 2026 a log cabin can be exempt two ways in Ireland: as a garden room up to 30 sq m (no sleeping), or under the new Class 3A exemption as a habitable garden dwelling of 32-45 sq m in the rear garden -- if you meet every condition and notify the council 14 days before starting. Mobile homes and caravans are still NOT exempt.

Exempt to 30 sq m
As a garden room
32-45 sq m
As a home (Class 3A)
14 days before
Council notification
Not exempt
Mobile home / caravan

Rules have conditions, and the conditions are where projects fail. Answer a few questions about your exact situation and get a plain-English answer with the regulation cited.

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The rules for a log cabin

  • 1.Two separate exemptions now apply. Non-habitable garden room: up to 30 sq m combined with all other outbuildings, rear garden, 4m pitched / 3m other roof height.
  • 2.Habitable garden dwelling (Class 3A, SI 340/2026, since 27 July 2026): 32-45 sq m, rear garden only, connected to the main house's services, and it must be a permanent building meeting the Building Regulations.
  • 3.Class 3A requires WRITTEN NOTIFICATION to the council at least 14 days before work starts -- skip it and the exemption does not apply.
  • 4.Class 3A is time-limited: works must start and finish between 27 July 2026 and 31 December 2030.
  • 5.Mobile homes and caravans are expressly excluded -- Condition 5 says the structure must not be 'temporary in nature, such as a caravan or mobile home'. Living in one still needs permission.
  • 6.Anything between 30 and 32 sq m falls in a gap: too big for a garden room, too small for Class 3A. Size deliberately.
  • 7.Exemptions never apply to protected structures or in Architectural Conservation Areas.

Reference: Classes 3 and 3A, Schedule 2, Part 1, as amended by S.I. 340 of 2026

Frequently asked questions

Can I live in a log cabin in my parents' garden?

Since 27 July 2026, yes -- if it qualifies under Class 3A: a permanent building of 32-45 sq m in the rear garden, linked to the house services, built to Building Regulations standard, with written notice to the council 14 days before starting. Outside those limits you still need planning permission.

Sellers say their log cabins don't need planning permission. True?

Partly true since July 2026, but the conditions are strict. A garden room under 30 sq m with no sleeping use is exempt; a habitable cabin needs to hit 32-45 sq m, be a permanent Building-Regs-compliant structure in the rear garden, and be notified to the council. A mobile home or caravan is never exempt, and enforcement falls on you, not the seller.

Turns out you need permission?

Start with the pre-submission checklist, estimate costs with the fee calculator, and read the step-by-step application guide. For uncertain cases, a Section 5 Declaration from your council (~€80) gives a formal ruling either way.

Need help with your application?

Tell us about your project and we'll connect you with an architect or planning consultant in your county. Free, no obligation.

Related projects

Garden Room →Garden Shed →Home Office →

This page is general guidance on the Planning and Development Regulations 2001 (as amended), not legal advice. Exemptions do not apply to protected structures or in Architectural Conservation Areas, and conditions apply in every case. Confirm with your local authority before starting work.