Planning Permission for a Renovation in Ireland: What Needs It, What Is Exempt

Last updated: 17 August 2026 · By Mossy Tariq, Founder — Property Blueprint Co.

Most Irish renovations do not need planning permission — and that sentence, read on its own, is how homeowners get into trouble. A new kitchen, a re-fitted bathroom, a converted utility room: none normally requires an application, because internal alterations are exempt while the domestic use of the house does not change. The homeowner hears that and relaxes.

The relaxation is the mistake, because Ireland runs two separate approval systems and the exemption only switches off one of them. Planning permission governs what the development looks like from outside and how the property is used. The Building Regulations — the Technical Guidance Documents, the TGDs — govern whether the work is sound, fire-safe, ventilated and drained, and they apply to the exempted kitchen as fully as to the extension next door.

Planning permission asks whether you may build it. The Building Regulations ask whether it is built right. Every renovation answers both.

What follows is the 2026 position: the exemptions and their exact limits, what always needs permission, the €80 mechanism that settles arguments in writing, and what happens when someone builds first.

Does an internal renovation need planning permission in Ireland

No — internal works are not planning matters while the use stays domestic. The Office of the Planning Regulator's guidance is explicit: any internal alteration is permitted as long as the use does not change. Strip the kitchen to the block walls, reconfigure the bathroom — the planning system is not engaged, because nothing the street or the neighbours can see has changed. External repair and maintenance sits in the same category, provided it does not make the house materially inconsistent with its neighbours — and none of this applies to a protected structure.

That answers the planning question — not the approval question, and the difference is the most useful thing an Irish homeowner can understand before booking trades.

What is the difference between planning permission and the Building Regulations

Planning permission is the local authority's consent to the development itself — footprint, height, external appearance, effect on neighbours, use of the land. Applications are public, and neighbours can lodge observations.

The Building Regulations are the separate legal standard for how work is carried out, set out in the Technical Guidance Documents — structure under TGD A, fire safety under TGD B, drainage under TGD H — and they apply whether or not permission was ever required. Knocking the wall between kitchen and dining room needs no planning permission; if it is load-bearing, the beam must still be engineered to TGD A and the certificate kept in the property file.

This is the two-regime distinction the phrase "you don't need planning" quietly erases. Exemption from planning is not exemption from compliance. The gas work still needs an RGI-registered installer, the new circuits a Safe Electric certificate, and the under-limit extension still meets every TGD from foundations to insulation. A renovation that treats the exemption as the end of the paperwork discovers the rest at the snag list — or at resale, when the solicitor asks for certificates nobody produced.

Which renovation projects are exempted development

Exempted development is the legal category of works that need no planning application, and each exemption holds only while every condition attached to it is met. These are the limits that matter, as set out by Citizens Information and the underlying regulations:

1. Rear extensions up to 45 square metres are exempt — cumulatively. It must be to the rear, must not rise higher than the house, and the 45 counts every previous extension, including a previous owner's. A house that gained a 20 square metre kitchen extension in the 1990s has 25 left, not 45.
2. Above-ground-floor extensions carry tighter caps. An extension above ground level must sit at least 2 metres from every boundary, capped at 12 square metres for a terraced or semi-detached house and 20 for detached.
3. The garden you keep is part of the exemption. An extension must not cut the private open space at the rear below 25 square metres — a deep extension across a short city garden fails on this alone.
4. Attic conversions are exempt while the roof profile stays untouched. Convert within the existing roof and the planning system is not engaged; add a dormer, raise the ridge, or put roof windows on the front slope and it generally is — rear rooflights are the exempt route to daylight.
5. Porches are exempt at 2 square metres. A front porch needs no permission at or under 2 square metres, at least 2 metres from any public road or footpath, and under 4 metres high with a tiled or slated pitched roof, or 3 metres otherwise.
6. Garden structures are exempt at 30 square metres combined. A shed, garage or garden room behind the building line is exempt to 30 square metres of such structures combined — 4 metres high pitched, 3 flat — provided 25 square metres of open space remains and it is not lived in or used commercially. Boundary walls and timber fences are exempt to 1.2 metres at the front and 2 metres at the side or rear.

These are the amended limits: on 27 July 2026 the Government's new exempted-development regulations came into force as S.I. No. 338 of 2026, raising the rear-extension allowance from 40 to 45 square metres and garden structures from 25 to 30 — with the open-space, height and boundary conditions unchanged. A glazed rear addition runs on the same 45 square metre logic, which is why the sunroom cost guide for Ireland treats the planning check as part of the price.

What always needs planning permission

Some categories sit outside the exemptions no matter how modest the work: the State reserves judgement wherever the development changes what the public sees or how the property is used.

Protected structures need permission for almost everything. On a protected structure the standard exemptions do not apply, and any work that would materially affect the building's character — including internal work — requires permission. The mechanism that keeps owners right is the Section 57 declaration — the local authority's written list of what it considers exempt for that building. It comes before the designer, not after.

Material change of use needs permission regardless of building work. Converting a garage into business premises, opening a crèche, running a bed and breakfast beyond four guest bedrooms — all engage the planning system without a single wall moving. The trap is the short-term let: in a Rent Pressure Zone, letting your entire home for short stays beyond 90 days a year — or short-term letting a property that is not your principal private residence — is a change of use requiring permission. The homeowner who converts a granny flat into a short-let unit has made two planning decisions; the second generates the enforcement letters.

Front and boundary works face the street, so the street gets a say. New or widened access to a public road always needs permission; so does a front wall above 1.2 metres and, on most streets, any dormer or roof window facing the road. Ground-level changes beyond a metre fall outside the garden exemptions too. How the whole-house numbers stack alongside this layer is set out in the room-by-room cost guide for Ireland.

How does a Section 5 Declaration settle the question

When the exemption is arguable, Irish law provides a definitive answer on demand. Under Section 5 of the Planning and Development Act 2000, any person can request a formal declaration from the local authority on whether a specific proposal is exempted development. Applications go in writing with drawings and a site map, the fee is €80, and the result is a written ruling; the outcome can be referred to An Coimisiún Pleanála.

The declaration does two jobs: before the build, it converts a builder's opinion about the 45 square metre rule into the planning authority's binding one; at sale, it answers a buyer's solicitor in one page. The discipline runs in reverse when buying a renovated house — the seller's extension is the buyer's enforcement risk, because unauthorised development transfers with the title.

What happens if you renovate without planning permission

Carrying out development that needs permission without having it is an offence, backed by substantial fines and, in serious cases, imprisonment. The practical machinery is more mundane: a complaint — usually from a neighbour — a warning letter, then an enforcement notice requiring the work to be undone or regularised. The regularisation route is retention permission, which costs a multiple of the standard fee and can be refused — and a refused retention application on an extension is an instruction to demolish it.

Then there is the seven-year rule, the most misunderstood sentence in Irish planning. After seven years, the local authority generally cannot begin enforcement action against an unauthorised development. Homeowners hear an amnesty. It is not one. The works never become authorised — the seven years bars the enforcement action, not the illegality — so the unauthorised extension surfaces at every future sale. The rule protects a homeowner from the council; it does not protect the sale price from the truth.

The economics run one way: a domestic extension application is €34, a Section 5 declaration €80, retention a refusable multiple. Checking first is the cheapest planning decision available.

Where does planning sit in the renovation sequence

Before the trades — every time. An Irish planning application is a public, fixed-tempo process: a newspaper notice and a site notice standing five weeks, a decision due within eight weeks of lodging (longer if further information is requested), then a four-week window for appeals to An Coimisiún Pleanála before the grant issues. Run cleanly, that is roughly three months. Permission lasts five years. Applications lodge through your local authority or the national Online Planning portal; the Office of the Planning Regulator's guide to work around the house is the reference to read first.

The sequencing failure is booking trades against a decision that has not issued: a builder booked for September against a July application is a deposit at the mercy of a further-information request, and every condition on the eventual grant lands mid-build as a variation the quote never priced. The prepared homeowner runs it in the other order: planning position confirmed in writing, then design frozen, then quotes, then contracts. It is the discipline that governs reading a renovation quote in Ireland, and the Competition and Consumer Protection Commission makes the same point on the contract side: agree terms in writing before work starts. Who you hand that contract to is its own discipline — how to find a builder you can trust in Ireland sets out the vetting stack that stands in for the missing licence.

Within The 12-Phase System — Property Blueprint Co.'s framework for running a renovation from brief to final sign-off — the planning check sits in the first phase, before budget validation, because its answer changes the budget. The full sequence is in The 12 Phases of a Renovation in Ireland, phase one is where the 45 square metre question is answered for €80 instead of by an enforcement notice.

What a single article cannot do is run the checks for your house — the cumulative arithmetic, the open-space measurement, the protected-structure register, the TGD trail behind each trade. That is what the Renovation Blueprint systems are built for: the planning and compliance checkpoints in sequence, with the budget, quote and contract disciplines they protect. The Full Home Renovation Blueprint runs the same system across the whole house.

If the cost baseline is the right first step, use the free Renovation Cost Calculator — a trade-by-trade estimate for the specific renovation, in under 5 minutes, before any trade has quoted.

Frequently asked questions

Do you need planning permission to renovate a house in Ireland?

Usually not for internal work. Kitchen, bathroom and utility renovations and rewiring are exempt while the domestic use of the house does not change. Permission is needed for extensions beyond the exemption limits, dormers and front roof windows, protected structures, new road access, and material changes of use. The Building Regulations apply either way.

How big can you build an extension without planning permission in Ireland?

Up to 45 square metres to the rear, counted cumulatively — the total includes every previous extension, including an earlier owner's. It must leave 25 square metres of open space at the rear, and above-ground floors are capped at 12 square metres for terraced or semi-detached houses or 20 for detached. The limit rose from 40 to 45 square metres on 27 July 2026, when S.I. No. 338 of 2026 came into force.

Do you need planning permission for an attic conversion in Ireland?

Not while the conversion stays inside the existing roof. Rear rooflights and an unchanged roof profile are generally exempt; a dormer, a raised ridge, or roof windows facing the road generally require permission. The Building Regulations separately decide whether the space qualifies as a habitable room — a stricter test that applies even when no permission is needed.

What is a Section 5 Declaration and how much does it cost?

It is a formal written ruling from your local authority, under Section 5 of the Planning and Development Act 2000, on whether a specific proposal is exempted development. The fee is €80, applications go in writing with plans and a site map, and the outcome can be referred to An Coimisiún Pleanála. It converts an opinion into a binding answer and closes the planning question at resale.

What happens if you build without planning permission in Ireland?

Unauthorised development is an offence carrying significant fines and possible imprisonment, and the council can order the work undone. Retention permission can regularise a genuine mistake, but it can be refused — a refusal on an extension means demolition. After seven years enforcement is generally barred, but the works never become authorised, so the problem resurfaces at every sale.

How long does planning permission take in Ireland?

Around three months when it runs cleanly: a site notice standing five weeks, a decision due within eight weeks of lodging, then a four-week appeal window before the grant issues. A further-information request restarts the clock. Permission lasts five years. Hold the decision in writing before booking trades.