Dún Laoghaire-Rathdown development plan
The Dún Laoghaire-Rathdown County Development Plan 2022-2028 sets the rules Dún Laoghaire-Rathdown County Council uses to decide planning applications. Here is what it controls, the local rules that matter to householders, and where to read the official plan.
The plan at a glance
- Plan
- Dún Laoghaire-Rathdown County Development Plan 2022-2028
- Period
- 2022 to 2028
- Status
- Made 9 and 10 March 2022, in effect from 21 April 2022
- Checked
- 29 Oct 2026
Variation No. 1 has since changed parts of Chapter 12 and the zoning text.
What a development plan controls
Every council has one. It is written for a set number of years and changed in steps called variations. It covers four things that matter most to a homeowner.
Every piece of land has a zoning, such as residential, town centre or agriculture. The zoning says what can be built there. An extension is usually fine in a residential zone. A new house on land zoned for agriculture usually is not, unless a rural housing rule allows it.
Outside towns and villages, the plan decides who can build a one-off house. Councils often ask for local ties, such as family land or years of living in the area, and may attach an occupancy condition.
The plan uses flood zones. New homes in Flood Zone A or B can face a justification test and a flood risk assessment. The official flood maps are on floodinfo.ie.
The plan lists protected structures and architectural conservation areas. If your home is in one, works that are normally exempt may need permission. You can ask the council for a declaration under section 57.
Key local policies in Dún Laoghaire-Rathdown
Plain-English summaries of rules in the Dún Laoghaire-Rathdown County Development Plan 2022-2028 that often decide a householder's project. Each one links to the council's own text.
Extensions, attics and garden rooms
The design rules the council uses when it looks at work on an existing home.
Front extensions are acceptable in principle if scale and design are right, but a significant break in the front building line is resisted, and a driveway length of at least 6 metres should be kept. Ground floor rear extensions are judged on length, height, closeness to boundaries and the garden left. First floor rear extensions are only permitted if there is no significant harm to neighbours. First floor side extensions that match the house are generally acceptable.
Source: Written Statement, Chapter 12, section 12.3.7.1 (i) to (iii)Dormers are judged on the character of the house and the privacy of neighbours. They should be set back from the eaves, gables and party boundaries, and set down from the ridge so they do not read as a third storey at the rear. Large, visually dominant dormers get careful scrutiny.
Source: Written Statement, Chapter 12, section 12.3.7.1 (iv)A granny flat linked to the main house is generally viewed favourably if it is smaller than the main house and can be absorbed back into it. It cannot be let or sold separately. A detached habitable room in the garden (playroom, gym, study) should be modest in size, and cannot be a granny flat or be let or sold separately from the main house.
Source: Written Statement, Chapter 12, sections 12.3.7.3 and 12.3.7.4Summaries checked 29 Oct 2026. They are plain-English guides written from the council's plan. They may be incomplete or out of date, and a variation can change the wording. They are not legal advice, so please check anything important with the council.
How it affects your project
The plan matters most when a project needs planning permission. Many small jobs are exempt, so check that first.
Many small extensions are exempt, so the plan only counts if you need permission, or your home is protected, or an earlier permission has conditions. When permission is needed, the council checks the design against the plan, for example overlooking, daylight and the garden left. See the Dún Laoghaire-Rathdown extension rules. Read the extension guide.
Small sheds are often exempt. A garden room used as a separate home, or a large one close to a boundary, can need permission, and then the plan's rules on extra accommodation apply. Read the shed guide.
A new house needs land where the zoning allows it. In the countryside, the rural housing rules decide who can build. Flood zones, access and wastewater also count. Read the new house guide.
Where to read the official plan and map
Always check the council's own copy. Plans are varied from time to time, and the zoning map is the legal record of how your land is zoned.
Check your Dún Laoghaire-Rathdown site before you apply
The pre-planning report covers zoning, protected structures, ground conditions and every application near your address, with the decisions.
Common questions about the Dún Laoghaire-Rathdown development plan
What is the Dún Laoghaire-Rathdown development plan?
The Dún Laoghaire-Rathdown County Development Plan 2022-2028 is the main planning policy document for Dún Laoghaire-Rathdown County Council. It covers 2022 to 2028 and sets the zoning of land and the local rules the council uses when it decides planning applications.
Where can I see the zoning for my land in Dún Laoghaire-Rathdown?
Zoning maps are part of the plan. Open the plan on the Dún Laoghaire-Rathdown County Council website, or use the national viewer at myplan.ie, which shows zoning for councils that have supplied it. Plans can be varied between full reviews, so check the council's own copy for the latest.
Does the Dún Laoghaire-Rathdown development plan matter if my project is exempt?
If your extension or shed is exempt development, you do not need planning permission, so the council does not assess it against the plan. The plan still matters if your home is a protected structure or in a conservation area, or if an earlier permission has conditions. Our free checker screens your project.
Can I build a house on family land in Dún Laoghaire-Rathdown?
It depends on the zoning of the site and on the rural housing rules in the plan. Councils usually ask for proof of local ties and attach an occupancy condition. Read the rural housing section of the official plan, and book a pre-planning meeting with the council to test your case.
Plan details compiled from Dún Laoghaire-Rathdown County Council's own website, source page, checked 29 Oct 2026. This page is a guide, not legal advice. Sources and methodology.