Guides
Extending a house in Ireland, explained.
Planning, costs and the realistic options for different kinds of house. Each guide is dated, sourced, and tells you what to verify.
Planning
- Do I need planning permission for an extension in Ireland?How exempted development works for house extensions in Ireland: the 40m² limit, upper floors, the 25m² garden rule, boundaries, earlier extensions and when you need to apply.
- Planning permission vs Building Regulations: what’s the difference?Planning decides whether you can build. Building Regulations decide how. Why an exempt extension still needs to comply, and what BCAR means for extensions over 40m².
- Building over or near a public sewerWhy the drain in your back garden can change your extension, and when you need Uisce Éireann’s consent.
Costs
Extension types
- Single-storey rear extensions in IrelandThe most common Irish extension: typical sizes, how to stay within exempted development, light, drainage and what drives cost.
- Side extensions and side-return infillsUsing the space beside your house: side extensions, two-storey side extensions and side-return infills on terraced and semi-detached homes.
- Two-storey extensions in IrelandAdding a bedroom and living space in one build: when a two-storey extension can be exempt, why most need permission, and how cost compares.
- Attic conversions and dormers in IrelandConverting the attic to a habitable room: head height, stairs, fire safety, dormers and planning — and why a non-compliant attic room isn’t a bedroom.
Property types
- Extending a terraced houseSide returns, short gardens, party walls and access: what works when extending a terraced house in Ireland.
- Extending a semi-detached houseRear, side, two-storey and wraparound options for Irish semi-detached houses, with the planning and cost trade-offs.
- Extending a detached houseMore room to manoeuvre: larger upper-floor allowance, side and wraparound options, and keeping proportions right.
- Extending a bungalowRear and side extensions, attic conversions and the trade-offs of going up on an Irish bungalow.
- Extending a cottageRespecting the character of an Irish cottage: modest rear extensions, glazed links, damp, and protected structures.