Planning permission
for garden rooms in Ireland.
In most cases, no planning permission is required. Here is what the legislation actually says — for both the Republic and Northern Ireland.
The short answer
A garden room at the rear of your house, under 30 m² (Republic of Ireland) or within 50% of curtilage (Northern Ireland), is generally exempt from planning permission as a matter of law. The technical term is exempted development (ROI) or permitted development (NI). No application, no decision, no fee.
- Do I need planning permission for a garden room in Ireland?
- In most cases, no. Under Irish planning law, garden rooms are exempt from planning permission provided they meet the size, position, and height criteria — primarily that the structure is under 30 m² (from 27 July 2026; previously 25 m²) and 25 m² of open garden space remains.
- What is the maximum size for an exempt garden room in Ireland?
- The maximum permitted size under the exemption is 30 square metres (approximately 320 sq ft), increased from 25 m² on 27 July 2026. You must also retain at least 25 m² of open garden space after installation.
- Are there height restrictions?
- For mono-pitch designs like Sprout Pod garden rooms, the maximum permitted height is 3 metres. All our standard designs are under 3 metres.
- Are there restrictions on window positions?
- Yes. There should be no window positioned within 1 metre of a neighbouring boundary.
- Can I place the garden room at the front of my property?
- No. The exemption applies to structures positioned to the rear or side of the property. Side placement requires either appropriate screening or a finish matching the existing building facade.
- Can I use the garden room as a sleeping space?
- Not a standard garden room — that exemption is for non-habitable use (offices, studios, gyms, leisure). However, since 27 July 2026 there is a separate new exemption — a Class 3A Detached Auxiliary Dwelling of 32–45 m² — which can be lived in, for family use, subject to conditions. See the questions below.
- Do I need to inform my neighbours?
- You are not legally obligated to notify neighbours under the exemption. However, courtesy notification is generally recommended, particularly if the structure is close to a shared boundary.
- What is a Detached Auxiliary Dwelling (Class 3A)?
- It is a new exemption introduced on 27 July 2026 that allows a detached, habitable dwelling of 32–45 m² to the rear of your home — for family use, such as an adult child, a parent or a live-in carer — without a full planning application. It is linked to the main house's services and can only be used alongside the main home. It cannot be sold, subdivided or short-term let separately.
- What conditions apply to a Detached Auxiliary Dwelling?
- It must be 32–45 m² (counting any existing garden structures towards the 45 m² cap), used only in conjunction with the main house, built to Building Regulations including fire safety, served by the main house's water and wastewater, and kept at least 0.6 m from any boundary. You must give the local planning authority at least 14 days' written notice before starting, retain at least 25 m² of private garden, and the main house must be your sole or main residence. The exemption is time-limited and the works must be completed before 31 December 2030.
- Do I have to tell the council before building a Class 3A dwelling?
- Yes. For a Class 3A Detached Auxiliary Dwelling (and for a Class 1A subdivision) you must notify your local planning authority at least 14 days before work commences, using the notification template in the regulations. It is not a planning application, but it is mandatory. We can help you prepare it.
- Does the Detached Auxiliary Dwelling exemption expire?
- Yes. The Class 3A exemption is time-bound — the dwelling must be completed before 31 December 2030 to rely on it. The standard 30 m² garden room exemption is not time-limited.
- What about Northern Ireland?
- Northern Ireland follows the General Permitted Development Order (GPDO) 2015. Rules are broadly similar — structures must be in the curtilage of a dwelling, not forward of the principal elevation, and within permitted height and footprint limits. We recommend checking with your local council for up-to-date guidance.
This page is for general information only and does not constitute legal advice. Planning legislation is subject to amendment and varies by local planning authority. If your project is in a protected structure, an Architectural Conservation Area, or subject to conditions attached to a previous planning permission, you should seek independent advice.
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