One of the first questions we hear from customers across Ireland is simple: "Do I need planning permission for a garden room?" The good news is that in many cases, you don't — as long as your structure stays within the exempted development rules.
Updated September 2026: new exempted development regulations came into force on 27 July 2026. This guide reflects them.
Garden Rooms: Now Up to 30 m²
The exemption for a structure in the back garden — such as a home office, studio, gym or store — increased from 25 m² to 30 m² on 27 July 2026. It still comes with conditions:
- Location: the structure sits in the back garden, not in front of the house.
- Garden space: enough private open space must remain after the build.
- Height: height limits apply, and they depend on the roof type.
- Use: the room is not used as a separate dwelling. Home offices, studios, gyms and hobby rooms are fine.
New: Detached Auxiliary Dwellings of 32–45 m²
A new exemption allows a detached auxiliary dwelling of 32–45 m² to the rear of the main house, linked to its services. You must notify your local authority 14 days before work starts, and further conditions apply. This is the route for family accommodation such as a granny flat.
When You Still Need Permission
A building larger than these limits, a dwelling below 32 m², one placed forward of the house, or one used for short-term letting generally needs a planning application. Our team prepares the drawings and specifications. See our planning and regulations guide for the full process.
Source: South Dublin County Council — New Exemptions 27.07.26. This is general information, not legal advice: always confirm your site with your local authority or a planning professional.
Start with the Right Model
Many of our compact studio cabins are designed with the exemption limits in mind. If you want a larger family unit, we'll help you prepare the drawings and documents your County Council needs.
Not sure which route applies to your site? Contact us for a free consultation — we'll assess your garden and tell you exactly where you stand.