27 Thornhill Road, Mount Merrion, Blackrock, Co. Dublin A94 N8C5
Construction of a first-floor rear bedroom extension and replacement of a ground-floor flat roof parapet.
D20B/0125 · Dun Laoghaire Rathdown County Council · Lodged 29 April 2020
- Reference
- D20B/0125
- Authority
- Dun Laoghaire Rathdown County Council
- Register status
- Decided
- Type
- Permission
- Received
- 29 April 2020
Summary
AI-generatedThe proposed development consists of constructing an extension to the rear bedroom on the first floor of the existing dwelling. It also includes replacing the flat roof parapet on the existing ground-floor extension.
Generated from the description above by an AI model and may contain mistakes. The council’s description is the authoritative record.
Official record
Development description
The development will consist of the construction of an extension to the rear bedroom on the first floor of the existing dwelling. The flat roof parapet to the existing ground floor extension will also be replaced.
Land-use zoning
What this land is zoned for
“A To provide residential development and improve residential amenity while protecting the existing residential amenities”
Objective set by the COUNTY DEVELOPMENT PLAN 2022-2028 (2022–2028). The planning authority decides each application on its own merits — this is the zoning context, not a compliance assessment.
Read the zoning objectives in the development planBuilt & sold
What happened next
Beyond the decision: whether this development was built, and what property here has sold for.
Recent sales nearby
within 500 m| Address | Date | Price | Distance |
|---|---|---|---|
| 7 Clonmore Rd, Mount Merrion, Dublin | Sept 2025 | €1,400,000 | 91 m |
| 33 Clonmore Rd, Mount Merrion, Dublin | Apr 2026 | €1,425,000 | 93 m |
| 32 South Ave, Mount Merrion, Dublin | Jan 2026 | €1,725,000 | 169 m |
| 28 South Ave, Mount Merrion, Dublin | Sept 2025 | €1,400,000 | 171 m |
| 24 South Ave, Mount Merrion, Dublin | Dec 2025 | €1,580,000 | 177 m |
| 71 Trees Road, Mount Merrion, Co Dublin | Aug 2025 | €1,480,000 | 202 m |
| 98 Lr Kilmacud Rd, Stillorgan, Dublin | Jul 2025 | €1,187,000 | 222 m |
| 13 Redesdale Rd, Mount Merrion, Dublin | Sept 2025 | €850,000 | 224 m |
Nearby properties, not this site — a guide to local values.
Sources: Building Control Management System (commencement notices) and the Residential Property Price Register, licensed under CC BY 4.0. Records are matched to this application by location and may not be exhaustive; always confirm against the official source before relying on them.
Key dates
Timeline
- Application received29 April 2020
- Decision issued10 July 2020
In the area
Applications near this site
Other planning applications within about 500 m — what else is being proposed or built nearby.
- GrantedAt this site
Permission sought for proposed demolition of existing garage and construction of two story extension at side,…
27, Thornhill Road, Mount Merrion, Co. Dublin
D05A/0897Dún Laoghaire–RathdownLodged 13 Jul 2005Extension
- GrantedAt this site
Retention permission sought for 2 no. bay windows and canopy over at front and pyramid type rooflight in…
27, Thornhill Road, Mount Merrion, Co. Dublin
D06B/0569Dún Laoghaire–RathdownLodged 23 Jun 2006Retention
- GrantedAt this site
For demolition of garage and utility area to side and build on its location a 2 storey hipped end extension…
31, Thornhill Road, Mount Merrion, Co. Dublin
D05B/0667Dún Laoghaire–RathdownLodged 6 Sept 2005Extension
- GrantedAt this site
Amendments to previous planning permission D05B/0667 for demolition of side garage/utility and replacement…
31, Thornhill Road, Mount Merrion, Co. Dublin
D08B/0781Dún Laoghaire–RathdownLodged 17 Nov 2008Extension
- Granted30 m away
Permission is being sought for alterations and additions to an existing 2 storey semi-detached dwelling. The…
No.33 Thornhill Road, Mount Merrion, Co. Dublin
D20A/0658Dún Laoghaire–RathdownLodged 17 Sept 2020Extension
- Granted40 m away
Planning permission sought to demolish existing single storey side garage and construct an attached single…
35, Thornhill Road, Mount Merrion, Co. Dublin
D09A/0427Dún Laoghaire–RathdownLodged 26 Aug 2009Extension
- Invalid40 m away
Permission is sought for alteration of previously granted file Reg. Ref. (D09A/0427) to include modification…
35, Thornhill Road, Mount Merrion, Co. Dublin
D11A/0371Dún Laoghaire–RathdownLodged 4 Aug 2011Extension
- Granted40 m away
Permission is sought for alteration of previously granted file Reg. Ref. (D09A/0427) to include modification…
35, Thornhill Road, Mount Merrion, Co. Dublin
D11A/0443Dún Laoghaire–RathdownLodged 26 Sept 2011Extension
Related developments
Similar applications
Ranked by what these developments actually propose, not by matching words — so you can see how comparable applications were decided.
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D08B/0032Dún Laoghaire–RathdownLodged 25 Mar 2008
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D26B/0364/WEBDún Laoghaire–RathdownLodged 22 Jun 2026
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