Planning rules
Garden room planning permission in Cork
Usually not needed. A garden room is exempt if all sheds and garden structures together come to no more than 30 m², at least 25 m² of garden is left, it's behind the front wall, no higher than 3 m (4 m with a tiled or slated pitched roof), and it isn't lived in. The 30 m² limit applies since 27 July 2026; before that it was 25 m².
A plain guide, not legal advice. The council has the final word.
Free, no obligation. One local company prices it, not five.
The conditions
Class 3, all six conditions
- Behind the house. Nothing built forward of the front wall.
- 30 m² in total. The garden room plus any shed, garage or greenhouse already there. It was 25 m² before 27 July 2026.
- 25 m² of garden left to the back or side.
- Height. 3 m with a flat roof, or 4 m with a tiled or slated pitched roof.
- Finish. A structure to the side of the house matches the house.
- Use. Not lived in or slept in, and only for the enjoyment of the house: an office, gym, studio or playroom.
From S.I. No. 338 of 2026, in operation from 27 July 2026.
City or county
Cork City Council or Cork County Council
Ballincollig, Glanmire, Douglas, Frankfield, Grange, Blarney, Tower and Whites Cross joined Cork City on 31 May 2019. If you live there, or in the old city, it's Cork City Council. Carrigaline, Cobh, Midleton, Mallow and the rest of the county are Cork County Council.
| Town | Council |
|---|---|
| Cork city | Cork City Council |
| Carrigaline | Cork County Council |
| Cobh | Cork County Council |
| Midleton | Cork County Council |
| Mallow | Cork County Council |
| Youghal | Cork County Council |
| Bandon | Cork County Council |
| Fermoy | Cork County Council |
| Passage West | Cork County Council |
| Kinsale | Cork County Council |
| Carrigtwohill | Cork County Council |
| Clonakilty | Cork County Council |
| Macroom | Cork County Council |
| Charleville | Cork County Council |
| Mitchelstown | Cork County Council |
| Tower | Cork City Council |
| Crosshaven | Cork County Council |
| Bantry | Cork County Council |
| Skibbereen | Cork County Council |
| Kanturk | Cork County Council |
| Blarney | Cork City Council |
| Cloyne | Cork County Council |
| Dunmanway | Cork County Council |
| Rathcormac | Cork County Council |
| Watergrasshill | Cork County Council |
| Millstreet | Cork County Council |
| Castlemartyr | Cork County Council |
| Killumney | Cork County Council |
| Whitegate | Cork County Council |
| Kilworth | Cork County Council |
| Aghada | Cork County Council |
| Buttevant | Cork County Council |
| Newmarket | Cork County Council |
| Inishannon | Cork County Council |
Not sure?
The section 5 declaration
If you're not sure a room is exempt, ask the council for a section 5 declaration: its answer in writing on whether the work is exempt. Cork City Council asks for the request in writing, with a description of the proposal and the €80 fee. Worth having before you spend money on a room near the limits.
Outside the rules
When you need planning permission
- Over 30 m² with the other sheds and structures.
- Over 3 m high with a flat roof.
- Someone sleeps in it, or it's let.
- A business with customers or staff calling.
- A protected structure, or a condition on the house's own planning permission that removes exemptions.
For a unit someone lives in, the detached auxiliary dwelling exemption (Class 3A) covers 32 to 45 m², linked to the house's services, with notice to the council.
Towns
We cover all of Cork
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Questions
Questions people ask
What size garden room can I build without planning in Ireland?
30 m² in total for all sheds and garden structures, since 27 July 2026. It was 25 m² before.
How high can a garden room be without planning?
3 m with a flat roof, 4 m with a tiled or slated pitched roof.
How close to the boundary can a garden room be?
Class 3 sets no distance from the boundary. Building regulations, neighbours' light and gutters over the fence still matter.
Who do I ask in Cork?
Cork City Council for the city, Ballincollig, Douglas, Glanmire, Blarney and Tower; Cork County Council for the rest. Cork City Council's section 5 fee is €80.
Can I use my garden room as a bedroom?
Not under Class 3, which rules out living or sleeping in it.
Get a free quote for your garden room in Cork
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