Planning Permission Basics in Ireland

Quick answer: Most home alterations in Ireland need planning permission. The big exception is a rear extension up to 40 m² at ground floor (rising to 45 m² under proposed 2026 reforms), provided you stay 2 m from boundaries, keep at least 25 m² of rear open space, and aren't in a Conservation Area or extending a Protected Structure. Applying takes about 8 weeks for a decision plus a 4-week third-party appeal window. Fee for a domestic extension is €34. When in doubt, request a Section 5 declaration (€80) from your local authority for a written legal answer.

What planning permission is

Planning permission is the formal written consent of your local planning authority (county or city council) to develop, alter, or change the use of property. It's governed by the Planning and Development Act 2000 (as amended) and its associated regulations. Most physical changes to a property — including new builds, extensions, change of use, demolition, and many internal works — fall within the planning code.

Without permission, the work is unauthorised development. The council can issue an enforcement notice requiring you to undo the works, refuse to issue a Certificate of Compliance, and ultimately prosecute under the Act. Unauthorised works are also a major problem during a sale — buyers' solicitors raise pre-contract enquiries about every alteration, and missing planning permission is one of the most common reasons a sale gets held up.

What you can do without planning permission — "exempted development"

The Planning and Development Regulations 2001 (as amended) carve out a long list of exempted developments — works you can carry out without applying for permission. The headline residential exemptions:

Important caveats that disqualify the exemption regardless of size:

• The property is a Protected Structure (listed on the local authority's Record of Protected Structures) — every alteration needs permission.
• The property is in an Architectural Conservation Area (ACA) — the exemption is materially narrowed; some councils require permission for any external change.
• The works front a public road or open space — additional restrictions.
• The works affect a structure on the National Inventory of Architectural Heritage (NIAH) — special considerations apply.

The exemptions do not cover material change of use (e.g. dwelling → office, or splitting a single dwelling into apartments). Those always need permission.

Get a Section 5 declaration if you're not sure

If you're unsure whether your specific works are exempt, you can apply to your local authority for a Section 5 declaration under the Planning and Development Act 2000. You submit:

• A description of the proposed works.
• Plans and elevations.
• The €80 statutory fee.

The council issues a written declaration — usually within 4 weeks — confirming whether the works are exempted development or require permission. The declaration is legally binding and gives you a defensible record when a future buyer's solicitor raises queries. It's the cheapest and fastest way to put a contentious "is this exempt?" question to bed.

Coming changes — 2025/2026 reform package

The government is progressing a package of exempted-development reforms aimed at small home improvements. As of writing the headline proposals include:

• Increasing the rear-extension limit from 40 m² to 45 m².
• Easier rules for dormer windows and dormer extensions.
• New exemptions for modular buildings in back gardens (e.g. detached garden offices, granny annexes).
• Front-garden storage sheds and gate pillars added to exempted categories.

These are proposals at the regulatory-amendment stage; the formal signed Statutory Instrument is the operative date — check the Gov.ie planning press releases for the latest position before relying on a new exemption.

When you do need to apply — the planning process

A standard residential planning application runs as follows:

Step 1: Pre-application consultation

Most local authorities offer free pre-application meetings with their planning officers. Strongly recommended for anything non-trivial — get the council's preliminary view before you spend on architects' drawings.

Step 2: Newspaper and site notices

You must publish a public notice in an approved newspaper and display a site notice on the property describing the works. The site notice must remain in place for 5 weeks after lodgement. Both notices must follow a prescribed format.

Step 3: Lodge the application

Submit to the planning authority within 2 weeks of the newspaper notice. The application bundle:

• Completed planning application form.
• 6 copies of plans (architect-drawn, scaled, with site location map).
• Copy of the newspaper notice and the site-notice text.
• The statutory fee.

Typical fees:

• House extension or alteration: €34.
• New single dwelling: €65.
• Garden wall / fence: €34.
• Change of use of dwelling to multi-unit: significantly higher.

Step 4: Validation

The council has 2 weeks to confirm the application is valid (correct fee, correct notices, complete bundle). If invalid, you start over — the worst-case scenario is a 4-week delay.

Step 5: Public participation (5-week window)

Once validated, the application is published on the council's planning portal. Anyone can:

• Inspect the file at the council office or online.
• Make a written submission (objection or support) within 5 weeks of receipt of the application, paying the €20 observation fee.

The number of submissions varies wildly — a quiet rear extension might attract zero; a contentious neighbour boundary dispute might attract dozens. The planning officer reads every submission.

Step 6: Decision — typically 8 weeks total

The council must issue a decision within 8 weeks of lodgement. They may:

• Grant permission — with or without conditions.
• Refuse permission — with reasons.
• Request further information under Article 33 — stops the clock; you have 6 months to respond. Common for boundary, parking, or design issues. After your response the council has another 4 weeks.

Step 7: Appeal window (4 weeks)

Any party — you, an objector, or a third party — can appeal the decision to An Coimisiún Pleanála (the national planning body, formerly An Bord Pleanála, renamed and reconstituted under the Planning and Development Act 2024) within 4 weeks of the council's decision. Appeals are decided in 18–24 weeks on average. The Commission can confirm, reverse, or vary the council's decision.

If no appeal is lodged, permission is granted at the end of the appeal window. The grant is typically valid for 5 years — the works must commence within that window.

Retention permission — what to do if work has already been done

If you've discovered that previous works on the property were carried out without planning permission, you (or the seller) can apply for retention permission — the same process as a normal application but for works already complete. The council can:

• Grant retention (formalise the unauthorised works).
• Grant retention with conditions (e.g. reduce the extension; remove an unauthorised element).
• Refuse retention — in which case the council can enforce removal.

Retention applications are routine in Irish conveyancing. Most pre-1990s home alterations have some piece of unauthorised work, and retention is the standard remedy. Cost is the standard application fee plus your architect's time.

Protected Structures and ACAs

A Protected Structure is a building listed on the local authority's Record of Protected Structures because of its architectural, historical, archaeological, or cultural significance. Every external and internal alteration to a Protected Structure — including window changes, internal modifications, repainting, and even insulation upgrades — requires planning permission. Get specialist conservation advice; the standard exemptions do not apply.

Architectural Conservation Areas (ACAs) are wider neighbourhoods where the character of the streetscape is protected. ACA designation typically removes the exemption for external changes — even routine works like changing windows, doors, or roof colour may need permission. The exemption for purely internal works usually survives.

To check whether a property is a Protected Structure or in an ACA, look up the local authority's planning portal or its Development Plan map. Most authorities also publish this information on the National Inventory of Architectural Heritage site.

Compliance certificates — what matters when you sell

When you sell, your solicitor will require:

• Planning permission for every alteration that needed it.
• A Certificate of Compliance from an architect or engineer confirming the works as built match the granted permission.
• A Certificate of Exemption (or a Section 5 declaration) for any works claimed as exempted development.

Missing or unclear compliance documentation is one of the most common reasons an Irish sale gets delayed. Keep a folder of all planning documents and certificates for the duration of your ownership — it's the single best gift you can give your future self at sale time.

Key takeaways

• Most physical alterations to a home need planning permission. The big exception is a rear ground-floor extension up to 40 m² (proposed 45 m² under 2026 reforms), subject to boundary and open-space conditions.
• Protected Structures and ACAs narrow or remove the standard exemptions — get specialist advice if you own one.
• If unsure, get a Section 5 declaration (€80) from the council. It's legally binding and protects you at future sale.
• A standard application takes 8 weeks for the council decision plus 4 weeks for the appeal window. Budget 3–4 months total.
• Retention permission is the routine remedy for past unauthorised works. Don't panic if you discover them — apply.
• Keep your planning paperwork. Missing documentation is one of the most common reasons an Irish sale gets delayed.

For the sale-side mechanics (when your solicitor needs the permission paperwork) see After Your Offer is Accepted. For BER and energy upgrades on Protected Structures see BER Ratings Explained.