S.I. No. 340 of 2026 · in force since 27 July

Find out if your back garden qualifies. In about a minute.

Ireland's planning rules changed in July. A detached, habitable home of 32–45 m² can now go in a rear garden with no planning permission — if you meet every condition. We check all of them and write the planning notification you have to send — then show you the second filing, the one that needs a certifier.

Check my garden Free. No sign-up. Nothing to install.
32–45 m²
the size band Class 3A covers — there is a floor as well as a ceiling
1,590
days until the exemption expires on 31 December 2030 — work must be finished, not just started
14
days' written notice to your local authority before you can break ground

What the exemption actually allows — and what it doesn't

Most write-ups only cover the first column. The second is where people get caught.

✓ Allowed

  • A detached, habitable dwelling of 32–45 m² in your rear garden
  • No planning application and no planning decision to wait for
  • Occupied by your household, or as a home office or studio
  • On the planning side you notify the council; you don't ask permission

✕ Not allowed

  • Short-term letting is prohibited outright — Condition 19 of the regulations
  • Selling or subdividing it away from the main house
  • Anything under 32 m² or over 45 m², counting existing sheds and garages
  • Independent water, power or drainage connections
  • Investment or rental properties — owner-occupied principal residence only

! The exemption covers planning only

Building Control Acts and the Building Regulations still apply in full — structure, fire safety and Part L energy performance. Getting the planning side right does not make the building compliant. Any supplier who tells you otherwise is selling you a problem.

Concretely, from the Department of Housing's Auxiliary Dwellings information note of July 2026: you must appoint a competent builder and an Assigned Certifier and file a Commencement Notice with additional documentation through BCMS. There is no opt-out for this type of dwelling. And when the work is finished you cannot move in until the Certificate of Compliance on Completion has been registered by the authority.

What it costs

The answer is free. Keeping the letter costs EUR 5. No account, no trial, no subscription.

Free

  • Every Class 3A condition tested against your own measurements
  • Both statutory notices explained, including the Commencement Notice most write-ups omit
  • What it costs you in professionals: a certifier is mandatory and cannot be opted out of
  • The full result emailed to you — every condition, pass or fail, with the reasoning
  • The opening of your notification letter, so you can see it is real

EUR 5, once

  • The complete notification letter, to read, print and post
  • Kept at a permanent private link, with the result and the figures you entered
  • Frozen and dated. It still says what the rules were on the day, after they change
  • Class 3A expires 31 December 2030 — a buyer's solicitor in 2029 will ask

Why the answer is free

We design and supply energy-efficient garden dwellings and the heating and solar that goes in them. This checker exists because we would rather meet people at the point where they are working out whether they can build at all, than sell to someone who finds out too late that their plot does not qualify. If you never speak to us again, the checker still works. The EUR 5 is for the letter and for keeping it, not for the answer.

Manufacturers and installers

If you sell garden rooms or modular homes in Ireland, your customers are asking you this question right now. You can put the checker on your own site, under your own branding, and keep the enquiry.

Two lines of HTML, once we have issued you a key and added your domain. Email hello@easy-group.ai and we will set it up the same day — there is no charge.

<div data-breakground="your-key"></div>
<script src="https://breakground.build/embed.js" async></script>