Exempt does not mean unrestricted
The regulations set categories of development that may proceed without a planning application. For a house extension, conditions can cover total floor area, height, the amount of private open space left and the position of windows. Earlier extensions built after the relevant date can count towards the total.
Protected structures, architectural conservation areas, planning conditions and site-specific restrictions can change the answer. A contractor’s opinion is not a formal planning determination.
Check before committing money
- Gather the property’s planning history and drawings of previous extensions.
- Ask the local authority’s planning section which current rules and local constraints apply.
- Have the proposed dimensions and boundaries checked against every condition.
- If doubt remains, request a formal declaration on whether the work is development or exempted development.
Watch proposed rules versus rules in force
Planning exemptions have been under review. A government announcement about a proposed expansion is not the same as an operative regulation. Base the project on law in force on the date you start, and confirm late design changes too.
Sources and review record
- Department of Housing: Planning permission exemptions · accessed 11 July 2026.
- Cork City Council: Exempted development applications · accessed 11 July 2026.
This guide provides general information for the Republic of Ireland. Check the linked official guidance for your circumstances and current rules.