How close can my neighbour build to my house in Ireland?

Irish planning law does not set one universal minimum distance between a neighbour's new structure and your house. Instead, the relevant limits depend on the type of works: small domestic structures and extensions built as exempted development under Schedule 2 to the Planning and Development Regulations 2001 have their own conditions, including height restrictions that get stricter the closer a structure is to a boundary, and a requirement to retain adequate private open space.

For anything requiring planning permission — a two-storey extension, a structure that exceeds exempted floor-area or height limits, or a new dwelling — the local authority assesses the proposal against amenity standards in its county or city development plan. These typically address daylight and sunlight to existing windows, overlooking and loss of privacy, sense of enclosure, and general visual impact on neighbouring properties, often using guidance such as the 45-degree or 25-degree daylight rules used by planners, even though these are design guidelines rather than rigid statutory distances.

Because the assessment is site-specific, two apparently similar developments in different areas, or on different types of site, can be treated differently depending on orientation, existing separation distances, and the character of the surrounding area as set out in the development plan.