A second home in the back garden without planning permission
You can build a detached home in the rear garden of the house you live in without planning permission if it has a floor area of at least 32 m², stays within 45 m² together with your sheds and similar structures, is started and finished by 31 December 2030, and meets the other conditions below. You must tell the council at least 14 days before work starts.
Where the rule comes from
This is Class 3A, added to the Planning and Development Regulations 2001 by S.I. No. 340 of 2026 and in force since 27 July 2026. The Department's circular calls it a detached auxiliary dwelling. It is temporary: it only covers work commenced and completed within the period that ends on 31 December 2030.
Size and position
| Condition | Limit |
|---|---|
| Floor area of the garden home | at least 32 m² |
| Garden home plus structures already there under Class 3 (sheds, garages, stores…) | 45 m² at most |
| Height with a tiled or slated pitched roof | 4 m |
| Height with any other roof | 3 m |
| Distance from any wall or party boundary | at least 0.6 m |
| Windows, from the boundary they face | at least 0.6 m |
| Private open space left for the main house | at least 25 m² |
The building must be permanent. The regulation says it cannot be temporary in nature, and gives a caravan or mobile home as examples (mobile homes in the garden).
Services and access
- No separate utility connection, including water and wastewater. With a septic tank or other non-piped system, the building cannot sit on an approved percolation area, the existing treatment must have enough capacity for the extra load and meet the EPA Code of Practice, and no extra treatment unit can be added.
- No new vehicle or pedestrian entrance onto a road. Access to the garden home, on foot or by wheelchair, must be provided within the grounds of the main house.
Who can use it, and how
- The main house must be the owner's sole or main residence when the work starts.
- The garden home can only be occupied together with the main house. It cannot be sold or subdivided separately.
- It cannot be used for short-term letting.
- The exemption is not available if the main house has been divided into two homes.
- Building Regulations, including fire safety, and Building Control Regulations still apply.
The notice to the council
At least 14 days before work starts, send your council a notification. It must say that you intend to use this exemption, confirm that the site meets the requirements, give the reason, and include the location and the Eircode. Councils keep a record of these notices and report the numbers to the Minister each year. Ask your council how it wants to receive the notice.
Outside these limits
A garden home under 32 m², over the 45 m² total, with its own connections, or started after the end date needs planning permission. The application fee for a house is set out on planning fees. Applications go to your council, or online at planning.localgov.ie.
See also sheds and garden rooms and the drawing of the house.