A Seller’s Guide to Unauthorised Building Works

For many people, the conversation about planning compliance only begins when they decide to sell. That is often the moment when an attic conversion completed twenty years ago, a sunroom added by a previous owner, or a garage that quietly became a home office starts to look less like a feature and more like a problem. Buyers’ solicitors will ask probing questions, lenders will demand documentation, and any gap in the paperwork can stall, reduce, or even collapse a sale.

At McCarthy + Co Solicitors LLP, we often advise clients who are surprised to learn that works carried out in good faith, sometimes by a previous owner, are technically unauthorised. The good news is that, with early action and the right professional advice, most of these issues can be resolved before they derail a sale.

What counts as unauthorised building works?

In Ireland, planning law has applied to development since 1 October 1964, when the Local Government (Planning and Development) Act 1963 came into force. The current legislative framework is now provided by the Planning and Development Act 2024, which is being commenced on a phased basis and replaces the 2000 Act. Under that framework, any development that is neither an exempted development nor carried out under a valid planning permission is, in legal terms, unauthorised.

Works that require planning permission include building a house, building a large extension or making significant changes to an existing house, or significantly changing how you use your property. Common examples of works that turn out to be unauthorised include:

• Rear or side extensions that exceed the 40 square metre exempted development limit, or that breach height, boundary, or window restrictions.
• Attic conversions where the new space is used as habitable accommodation, particularly where dormer windows have been added.
• Garage or shed conversions that change the use of the structure (for example, to a granny flat, home office, or self-contained unit).
• Front porches and conservatories that are too large, too tall, or too close to the road.
• Internal subdivisions that create a separate dwelling unit.
• Changes of use, such as converting a residential property to short-term lets, a creche, or commercial premises.
• Works to a protected structure carried out without the required permissions, even where similar works to an unprotected building would be exempt.

How unauthorised works affect a property sale

In a normal conveyancing transaction, the seller is expected to provide evidence that the property complies with planning law and building regulations. The standard Law Society of Ireland Conditions of Sale include warranties about planning compliance, and it is now routine practice for the buyer’s solicitor to require a Certificate or Opinion of Compliance with planning permission and building regulations from a suitably qualified architect, engineer, or building surveyor.

If unauthorised works are uncovered during the sale process, the consequences can include:

• Delays of weeks or months while the issue is investigated and a solution is put in place.
• A reduction in the agreed sale price, or a retention of part of the price pending resolution.
• Difficulty for the buyer in obtaining mortgage approval, as lenders rely on the same compliance documentation.
• The buyer pulling out of the sale entirely, particularly in a market where alternative properties are available.
• In rare cases, enforcement action by the local authority, which can include orders to alter or demolish the works.

The seven-year rule and its limits

Many sellers have heard of the so-called seven-year rule and assume that it solves the problem on its own. It does not.

The rule derives from section 157(4) of the Planning and Development Act 2000 (and is carried over in equivalent provisions of the 2024 Act). It states that the local authority generally cannot take enforcement action against an unauthorised development more than seven years after the works commenced. Useful as that immunity is, the Office of the Planning Regulator and the courts have been clear that it does not convert unauthorised works into authorised ones. The works remain unauthorised; they are simply immune from enforcement.

There are also important exceptions. As confirmed by Cavan County Council’s guidance on enforcement, enforcement action may still be taken at any time where there has been a breach of a condition relating to the use of the land, regardless of how much time has passed. Quarrying and peat extraction are also treated differently.

For a seller, the practical point is that the seven-year rule does not produce a “clean” title. A buyer’s solicitor and a buyer’s lender are likely to insist on more than the passage of time. They will often want a statutory declaration from the seller, a planning search, and an architect’s or engineer’s opinion confirming when the works were carried out and that no enforcement action has been taken or threatened.

Planning compliance and building regulations are two separate issues

A point that often surprises sellers is that planning permission and building regulations are governed by entirely separate regimes. A property can be fully compliant with planning law and still fall short of the Building Regulations made under the Building Control Act 1990 and subsequent legislation, including the Building Control Regulations 1997 to 2024.

Building Regulations cover matters such as structural safety, fire safety, ventilation, energy performance, and accessibility. They have applied to most building work since 1 June 1992, with earlier works in some areas governed by the older Building Bye-Laws. As the Law Society’s Conveyancing Committee has confirmed, the introduction of the Building Control (Amendment) Regulations 2014 added further certification requirements for works subject to a commencement notice on or after 1 March 2014.

The result is that, even where a development qualifies as exempt from planning permission, or where the seven-year planning enforcement period has long since expired, the seller may still need to demonstrate compliance with the relevant Building Regulations.

Practical steps to take before going on the market

We often advise clients who are thinking about selling to address planning and building compliance well before the property is listed. The earlier the work is done, the more options are available, and the less leverage any issue gives a prospective buyer.

The steps we recommend include:

• Locate all planning documents in your possession, including grants of permission, decisions, conditions, drawings, and any prior Certificates or Opinions of Compliance.
• Carry out a planning search on your local authority’s online planning register to identify what was permitted and on what conditions.
• Engage an architect, chartered engineer, or chartered building surveyor to inspect the property and identify any works that may fall outside what was permitted or exempt.
• Where works are clearly authorised and compliant, ask the same professional to provide an Opinion or Certificate of Compliance in the Law Society standard format.
• Where works are arguably exempted development, but the position is not obvious, consider applying to the local authority for a section 5 declaration confirming that the works are exempt.
• Where works are unauthorised and within the enforcement window, consider applying for retention permission to regularise the position formally.

Retention planning permission

Retention permission is a specific form of planning permission that applies to works already carried out. It is not a soft option, and it is not guaranteed. The local authority will assess the application against the relevant development plan and planning policies in much the same way as a normal application.

The procedure broadly mirrors a standard planning application, including the requirement to publish a site notice, advertise in an approved newspaper, and submit detailed drawings. Statutory fees for retention applications are higher than for ordinary applications. Fees are deliberately set at a higher level to discourage development without permission and to reflect the additional work involved for the planning authority.

If retention is granted, the works are regularised, and a clean compliance opinion can usually follow. If it is refused, the seller is likely to be required to remove or alter the works, and there is a right of appeal to An Coimisiún Pleanála (formerly An Bord Pleanála) within four weeks of the decision.

The process can take several months from start to finish, which is a strong argument for starting early rather than waiting until a buyer is at the door.

Disclosure obligations to buyers

Sellers in Ireland do not generally owe a buyer the kind of broad pre-contract disclosure obligation that exists in some other jurisdictions. The principle of caveat emptor, or “buyer beware”, still applies to a significant extent. However, the standard contract for sale, the replies to pre-contract enquiries, and the warranties typically given by a seller all create real obligations to provide accurate information about planning and building compliance.

Misrepresenting the planning status of a property, or signing a statutory declaration that is not accurate, can expose a seller to a claim for damages, rescission of the contract, and, in serious cases, allegations of fraud. We strongly advise sellers never to sign declarations or replies to enquiries without first taking legal advice and ensuring that the position is properly understood.

Special situations to be aware of

A number of recurring situations can complicate a sale and warrant particular attention:

• Inherited or probate properties. Executors and beneficiaries are often unfamiliar with works carried out by the deceased, sometimes decades earlier. A planning search and a professional inspection are particularly important here.
• Properties bought without full compliance documentation in the past. As we have noted in our earlier post on why planning permission is important when buying a property, the day you buy is the day you sell. An issue that was overlooked at purchase will almost always resurface on sale.
• Properties in Rent Pressure Zones or that have been used for short-term letting. Change of use issues can be just as significant as physical works.
• Protected structures and properties in architectural conservation areas. Works that would be exempt elsewhere often require permission for these properties, and unauthorised alterations can attract particular scrutiny.

Require legal assistance with selling a property?

At McCarthy + Co Solicitors LLP, we have a long history of guiding clients through every stage of a property sale, including the careful handling of planning and building compliance issues. Whether you have already identified an unauthorised element to your property or simply want to make sure the paperwork is in order before going to market, our conveyancing team will be glad to assist. Arrange a consultation with a solicitor here by completing our quick and confidential online form.