Garden rooms without planning permission in Ireland: the 2026 rules
Since 27 July 2026, you can build a garden room of up to 30 square metres in your back garden without planning permission. That’s up from 25 square metres, as long as it meets a few conditions on height, position and how much garden you keep.
It’s one of the most common questions I’m asked at the moment. Here’s what the new rules mean in practice, and how to plan the garden around a new garden room so it looks like it was always meant to be there.
What changed in 2026?
The government updated the planning exemptions for homes, and the changes came into effect on 27 July 2026. For garden rooms, the key change is size. The exemption for a structure in the back garden, such as a shed, store, home office or gym, increased from 25 to 30 square metres.
Thirty square metres is a generous room: big enough for a home office with a meeting area, a gym, or a studio. The other conditions stay broadly the same.
The rules your garden room needs to meet
To build without planning permission, your garden room must:
Be no bigger than 30 m² in total. This includes any sheds or other garden structures you already have, so an existing 10 m² shed leaves 20 m² for the new room.
Sit behind the front of your house. It must be to the rear or side, never forward of the front wall line.
Stay within the height limits. No more than 4 metres high with a tiled or slated pitched roof, or 3 metres for a flat roof or any other roof.
Leave at least 25 m² of private garden. After the room is built, you need at least 25 square metres of private open space left for the house.
Not be lived in. It can’t be used as a bedroom, as living accommodation, or as a separate business open to the public.
Can I use it as a home office?
Yes. A home office, studio or gym used by the people living in the house is exactly what this exemption is for. What it doesn’t cover is sleeping accommodation, or a business with customers coming and going.
If you want a garden building that someone can live in, that’s a different exemption with different rules. I’ve explained it in Garden homes and granny flats: the 2026 exemption explained.
When you’ll still need planning permission
The exemption may not apply, or you may need permission, if:
the room would be larger than 30 m², or taller than the limits above
your house is a protected structure
an earlier planning permission on your house restricts further development
it would leave you with less than 25 m² of private garden.
If you’re not sure, check with your local council’s planning department before you start. Planning applications for garden rooms are one of the services I provide, so I’m happy to look at it with you.
Being exempt from planning permission doesn’t mean exempt from Building Regulations. Your builder or supplier should confirm the room meets them.
Planning the garden around your garden room
Most garden rooms are chosen from a brochure and then placed at the end of the garden. The result often looks like an afterthought. A little planning makes a big difference.
Position it for the light and the view
Think about where the sun is through the day, and what you’ll look at from the desk or sofa. Equally, think about how the room looks from the house. It will be the main thing you see from your kitchen window all year round.
Keep a garden you’ll actually use
Twenty-five square metres is the legal minimum, not a design target. Plan where the seating, lawn or play space will go before you fix the size of the room.
Connect it with a proper path
You’ll walk to it in the rain and the dark. A well-lit path in a good surface, such as granite, limestone or porcelain, makes the room feel part of the house.
Soften it with planting
Planting around the base and sides helps a new building settle in. Evergreen shrubs, a multi-stem tree or climbers on a nearby wall give it a sense of place, and screen it from neighbours.
Plan the services early
Electricity, broadband and drainage need trenches. It’s far easier to lay them before the new paving and planting go in.
[Add a short example: 2–3 sentences on a garden room project you’ve designed around. What the client wanted, where you placed it and why.]
Quick questions
Does the 30 m² include my existing shed?
Yes. The 30 m² is the total for all such structures in your back garden.
Can my garden room have a toilet?
It isn’t ruled out, but it can’t be used as living accommodation. Check with your council before you plan any plumbing.
Do I need to tell the council?
Not for a standard garden room that meets the rules. Notification applies to the new garden home exemption, which is separate.
Is this legal advice?
No. This is a general guide based on the 2026 regulations. Every site is different, so always confirm with your local council before you build.
Thinking about a garden room?
I can help you decide where it should go, design the garden around it, and handle the planning application if your plans fall outside the exemption. A site visit to talk it through is €120.
Official sources: Department of Housing announcement · South Dublin County Council: new exemptions from 27 July 2026
Written by Ingrid Smyth, garden designer, Dublin. Last updated November 2026.
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