Garden home, extension or garden room?
The short answer
Choose a garden home (32 to 45 m²) when someone needs their own front door and independence. Choose an extension (up to 45 m² exempt) when the extra space is part of daily family life. Choose a garden room (up to 30 m²) for an office, gym or studio that nobody sleeps in.
On this page
Side by side
| Garden room | Garden home | Rear extension | |
|---|---|---|---|
| Exempt size | Up to 30 m² | 32 to 45 m² | Up to 45 m² |
| Can sleep in it | No | Yes | Yes |
| Independent living | No | Yes | No |
| Notify council | No | Yes, 14 days before | No |
| Building Regulations | Limited | Full | Full |
| Disruption to the house | Low | Low | High |
| Deadline | None | Finish by end of 2030 | None |
All three need at least 25 m² of private open space to remain, and each has its own height and position rules.
When a garden home fits
- An older parent who wants to be close but keep their own space.
- An adult child saving for a home of their own.
- Your garden has side or rear access, since the garden home needs its own way in that doesn't go through the house.
- You want minimal disruption, especially with a modular unit built off-site.
When an extension fits
- You need a bigger kitchen, living room or extra bedroom inside the house.
- There's no side access, as in many mid-terrace homes.
- You want the space to add value to the main house as one property.
When a garden room is enough
- The space is for work, exercise, hobbies or play, not sleeping.
- You want the lowest cost and the simplest rules.
- You might want a garden home later. Keep any garden room small, since it counts against the 45 m² garden home total.
Common questions
Is a granny flat cheaper than an extension in Ireland?
A modular garden home can be cheaper per m² than an extension. A builder-built garden home costs about the same, because both must meet the Building Regulations for living space.
Can I have both an extension and a garden home without planning?
Each exemption has its own conditions, including keeping at least 25 m² of open space. Building both in one garden is likely to run into the open space rule, so check carefully or ask your council for a Section 5 declaration.
Sources
Garden room companies serving Dublin
See all Dublin companiesFeatured
Paid placements. Featured companies pay to appear here.
Reach people planning a garden room in Ireland. Featured spots appear at the end of every guide on this site.
Get featuredCompanies serving Dublin
Listed alphabetically, not ranked. How we list companies