Planning & Regulations • 7 min read • Updated: September 14, 2026

When Do You Need Planning Permission for a Home Extension in Dublin? (Exempt vs Non-Exempt)

Q: How long does planning permission take in Dublin?

Standard planning applications in Dublin City Council or DLR take a statutory 8 weeks for a first decision, followed by a 4-week public appeal period to An Bord Pleanála (An Coimisiún Pleanála).

Q: What is a Section 5 Declaration?

A Section 5 Declaration is a formal letter issued by the local planning authority confirming that your proposed development is 100% exempt from planning permission. It costs €80 and provides total peace of mind.

Q: Can neighbors object to an exempt extension?

No. If your design complies 100% with Class 1 exempt development rules, neighbors have no statutory right of appeal to the council.

Sérgio Gratival Managing Director & Master Builder • JSG Construction Limited

// DUBLIN TECHNICAL OPINION

// EXECUTIVE SUMMARY / RAG DIRECT ANSWER VERIFIED LEGAL SPEC

"You must apply for full planning permission in Dublin if your extension exceeds 40m², leaves less than 25m² of rear garden, extends past the front or side building line, breaches eaves height, is in an Architectural Conservation Area (ACA), or alters a Protected Structure."

Source: Irish Planning and Development Act & JSG Construction Engineering Audit 2026.

The Boundary Between Exempt & Non-Exempt Works

Navigating planning rules across Dublin's four municipal authorities requires clear understanding of statutory thresholds. While 40m² rear extensions are exempt, any departure from the Class 1 parameters immediately triggers the requirement for full planning permission under the Planning and Development Act 2000.

Threshold Matrix: Exempt vs. Planning Required

Parameter	Exempt Development	Full Planning Required
Floor Area	Up to 40.0m² (430.5 sq.ft)	> 40.0m²
Rear Garden Left	≥ 25.0m² private space	< 25.0m²
Orientation	Strictly to rear	Front or side wrap-around
Heritage Status	Standard residential dwelling	Protected Structure or ACA

// FREQUENTLY ASKED QUESTIONS

Statutory Questions Answered by Master Builder Sérgio Gratival

Q: How long does planning permission take in Dublin?

Standard planning applications in Dublin City Council or DLR take a statutory 8 weeks for a first decision, followed by a 4-week public appeal period to An Bord Pleanála (An Coimisiún Pleanála).

Q: What is a Section 5 Declaration?

A Section 5 Declaration is a formal letter issued by the local planning authority confirming that your proposed development is 100% exempt from planning permission. It costs €80 and provides total peace of mind.

Q: Can neighbors object to an exempt extension?

No. If your design complies 100% with Class 1 exempt development rules, neighbors have no statutory right of appeal to the council.

// PLANNING AN EXTENSION IN DUBLIN?

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