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

The short answer: often, no

Under Irish planning regulations, garden structures under 30m² that meet certain conditions — including setback from boundaries and not being used as a separate dwelling — are generally exempt from planning permission. That threshold rose from 25m² to 30m² on 27 July 2026, under new national exempted-development regulations (S.I. No. 338 of 2026). Most of the garden rooms and log cabins we build fall within this exemption. That said, "generally exempt" isn't the same as "always exempt," so we check every site individually rather than assuming.

What the 30m² exemption actually depends on

Size is the headline figure, but it isn't the only thing that decides whether a project is exempt. The exemption also depends on:

• Floor area — the structure, plus any other previous extensions or outbuildings in the same curtilage, generally needs to stay under the 30m² exempted threshold (raised from 25m² in July 2026).
• Height and distance from boundaries — how tall the structure is and how close it sits to your boundary lines both affect whether it qualifies.
• Remaining private open space — the house must keep at least 25m² of private open space after the structure goes in.
• Use — a home office, studio or gym is treated differently to a structure intended as independent living accommodation.

We build garden rooms from around 6m² up to 60m² and beyond. Most home offices and studios fall in the 12m² to 30m² range, which also keeps them inside the exemption. We review all of this against your actual site at the free site visit, so you get a clear answer before we ever talk about price.

If your project needs full planning permission

A larger structure, a second storey, or a garden room intended as separate living accommodation will typically need a full planning application. That isn't a reason to rule it out — we've built plenty of larger structures with full planning approval. We'll tell you clearly if your project needs one, advise you on what the process involves from experience, and build the typically longer timeline into your project plan rather than let it come as a surprise.

What about a granny flat?

"Granny flat" is a common search term for a self-contained garden annexe — one with its own kitchen and bathroom, built for a family member to actually live and sleep in, rather than a home office, studio or gym. Until recently that meant a full planning application in almost every case. As of 27 July 2026, that's changed: a new exemption (Class 3A, under S.I. No. 340 of 2026) allows a self-contained detached unit of 32m² to 45m² in a rear garden without planning permission, subject to real conditions:

• Occupied only by the homeowner's family — it cannot be sold, subdivided or let separately from the main house, and cannot be used for short-term letting.
• Linked to the main house's water and wastewater services, not a separate utility connection.
• A maximum height of 4m (pitched tiled/slated roof) or 3m otherwise, and at least 0.6m from any boundary.
• At least 25m² of private open space must remain at the main house.
• 14 days' written notice to your local council before work starts, and the build must be completed by 31 December 2030 — this is a time-limited exemption, not a permanent rule.

A garden room, home office or gym built under the separate, simpler Class 3 exemption (now 30m²) has none of these conditions — it's the more straightforward route if you don't need a self-contained living space. See our full breakdown of the new 45m² exemption rules for the complete picture, or we'll confirm which route suits your project at the free site visit, before any price is discussed.

Log cabins & home gyms

The same general exemption rules apply regardless of whether a structure is timber-framed, log-cabin style or block-built — Irish exempted development rules are based on size, siting and use, not construction method. We check this the same way for every build.

Other garden structures

If you're planning more than one project, here's the general picture for the rest of what we build. We'll confirm the specifics for your own site at the visit either way.

• Fencing — fences and garden walls up to 2 metres are generally exempt to the rear or side of a property, and up to 1.2 metres to the front. Corner sites, protected structures and certain planning schemes can change this.
• Patios & paving and decking — ground-level hard landscaping is generally not treated as a structure requiring planning permission, though raised decking or anything attached to the house can be assessed differently.
• Pergolas & outdoor kitchens — open-sided structures are usually treated more leniently than fully enclosed rooms, but size and proximity to boundaries still matter.

None of this is a substitute for local-authority advice on a specific site — it's the general national picture under the Planning and Development Regulations. We confirm the applicable rules for your own garden at the free site visit, and flag anything that needs to be checked with your local authority before we quote.