Neighbour Started Work Without a Party Wall Agreement?
The short answer is that the Act’s machinery is not available to you, and your ordinary legal rights are.
That sounds worse than it is. It is also, since 2023, settled law.
No notice, no Act
In Power v Shah [2023] EWCA Civ 239, decided on 7 March 2023, the Court of Appeal considered exactly this situation. A building owner carried out work, including an alleged chimney breast removal, without serving a notice. The adjoining owners appointed a surveyor under section 10, and when the building owner did not engage, that surveyor appointed one for him. The two surveyors made an award granting compensation and fees.
The Court of Appeal held the award null and void. Lord Justice Coulson put the reasoning this way:
In the absence of a notice, the dispute resolution mechanism in s.10 was not engaged and the Award produced in purported compliance with it was null and void.
Lord Justice Lewison gave the phrase the industry now uses:
In my judgment, unless the Act is triggered by the service of a party structure notice, the adjoining owner is not entitled to invoke the Act. In short, I agree with the judge that ‘no party structure notice, no Act’.
The court was clear about why. Section 3 requires a notice before the work: “The service of the notice in advance is mandatory … The service of the notice is therefore fundamental to the whole structure of this part of the Act.”
So an adjoining owner cannot force the process retrospectively. You cannot appoint a surveyor, have an award made, and recover under it, where no notice was ever served.
What you keep instead
This is the part that matters, and the court addressed it directly. Coulson LJ:
it is also common ground that an adjoining owner in the position of Mr and Mrs Panayiotou is not left without a remedy. On the contrary, the adjoining owner will have all the usual common law remedies which one would expect in this situation: the right to bring claims in trespass, nuisance and negligence, and the right, if appropriate, to seek an injunction.
Lewison LJ explained the mechanism. The Act replaces common law rights only when it is invoked:
The critical point here is that the adjoining owner’s common law rights are supplanted ‘when the statute is invoked’. The statute is invoked by the service of a party structure notice. Until that time, the position remains governed by the common law of trespass and nuisance.
And from the building owner’s side, at paragraph 96: “A building owner may rely on his common law rights, but in that event he is vulnerable to claims of trespass or nuisance.”
A building owner who skips the notice therefore gives up the Act’s protections — including the statutory authority to do the work at all — and exposes himself to claims he would not otherwise face.
Can you get a retrospective party wall agreement?
Not under the Act. There is no provision for a retrospective notice or a retrospective award, and no route to a party wall agreement after works completed. The Court of Appeal said so plainly. Coulson LJ:
The Act provides an important mechanism – because of the requirement for a notice - by which the scope of the work to be carried out can be agreed in advance. It was not intended to resolve disputes concerning the effect of works which, because of the absence of a notice, had already been completed.
Lewison LJ added that he could see no justification “for a provision which deems a building owner to have served a party structure notice under the Act when in fact he has not, such as to confer jurisdiction on a surveyor.”
An earlier first instance decision had suggested the Act’s provisions could operate retrospectively. Coulson LJ considered it and disagreed, saying he thought that judge “was wrong about retrospectivity in any event.”
Two honest qualifications. Power v Shah was about an adjoining owner trying to invoke the Act unilaterally. The court did not decide whether a building owner who has already started can serve a notice and bring the Act into operation for what remains. Authority quoted within the judgment suggests a later notice may give statutory authority going forward but does not wipe out liability already incurred — in the words quoted there, it “does not relieve him from liability for the continuing nuisance which he has unlawfully committed, until such time as and to the extent that such authority is obtained.”
And separately, neighbours are always free to settle matters between themselves in writing. That is a private contract, not an award, and the Act does not govern it.
Stopping work: injunctions, and their real cost
Government guidance answers the immediate question directly. On what to do if a neighbour starts work and no notice has arrived:
The Act contains no enforcement procedures for failure to serve a notice. However, if your neighbour or a builder carrying out work on your neighbour’s behalf starts work, without having first given notice in the proper way, you may seek to stop the work through a court injunction or seek other legal redress. You may wish to take professional or legal advice before commencing such action.
An injunction has been granted on facts like these. Power v Shah describes an earlier case in which, after work to a party wall without notice, the adjoining owner “obtained an interlocutory injunction restraining further work until the building owner had complied with the provisions” of the predecessor Act.
Be aware of what an injunction involves. Lewison LJ set out the practical downside candidly:
Mr Isaac said, with some force, that proceedings in court are potentially more costly than an award by surveyors; and that if an adjoining owner wished to obtain an interlocutory injunction they might be deterred by having to give a cross-undertaking in damages. But he also accepted that surveyors have no power to grant an injunction
Two further points from cases discussed in the judgment. The costs of contemplating or preparing court proceedings to compel a notice were held irrecoverable through the Act’s dispute resolution procedure. And proceedings to enforce common law or equitable remedies “fall wholly outside the 1996 Act” — as do preparations for them.
So the route exists, but it is a court route with court costs, and a surveyor’s award cannot recover them for you.
If a neighbour appears to be about to start without a notice, the guidance is simpler: tell them in writing about the Act before work begins. The party wall notice guide covers which notice they owe you.
Can a neighbour refuse a party wall agreement?
This is asked constantly, and the short answer is that a neighbour cannot refuse in the sense of stopping the work.
Generally no — an adjoining owner cannot veto notifiable work. Government guidance puts it plainly:
You cannot stop someone from exercising the rights given to them by the Act, but you may be able to influence how and at what times the work is done.
Refusing to engage does not block the process either:
if you refuse or fail to concur in the appointment of an agreed surveyor, or to appoint a surveyor of your own, the Building Owner will be able to appoint a second surveyor on your behalf so that the dispute resolution procedure can proceed without your co-operation.
What an adjoining owner actually has is a set of responses, each with a defined effect:
- Consent in writing within 14 days — no dispute arises, and the work proceeds as notified.
- Do nothing for 14 days — section 5 deems you to have dissented, and a dispute is deemed to have arisen.
- Dissent — the same result, reached deliberately.
- Serve a counter notice under section 4, within one month. This is often misunderstood: it lets you require additional work for your own convenience, such as chimney copings, jambs, flues or piers. It is not a way to stop the building owner’s scheme.
One genuine exception. For a brand new wall on the line of junction, refusal does bite. If the adjoining owner does not consent within 14 days, section 1(4) means the building owner may build only at his own expense and “as an external wall or a fence wall, as the case may be, placed wholly on his own land”. You cannot stop the wall, but you can stop it being built astride the boundary.
Consenting also does not switch off the building owner’s duties. Guidance notes that consent “is simply confirmation that, at that time, there is nothing ‘in dispute’”, and that if a difference arises later — over damage, for instance — the dispute procedure then applies.
No party wall agreement, selling house: what to expect
This is a real problem at conveyancing stage, and the position is partly settled and partly not.
You will be asked. The Law Society’s TA6 Property Information Form (6th edition), which replaced the 4th and 5th editions on 30 March 2026, asks at question 2.5 whether the seller is aware of any notice being served or received under the Party Wall etc. Act 1996 in respect of shared or party walls or boundaries, and asks for a copy and details of works if so.
The Law Society’s own explanatory notes for sellers are specific:
If you’ve carried out building work on a shared boundary, you or your architect, surveyor or solicitor at the time should have sent a written notice to your neighbour.
You should attach any notices to the TA6 form and give details of the work carried out in question 2.5.
If you think building work has been carried out that affects a boundary feature, but you can’t find a notice, contact your solicitor for advice.
Note what question 2.5 asks about: notices. A seller who did notifiable work and served nothing can answer it accurately and still leave a problem behind. Other questions on the same form reach further — whether you are aware of disputes or anything that might lead to one, whether you are aware of notices or communications affecting the property, whether alterations included removal of internal walls or removal of a chimney breast, and whether any work lacks necessary consents.
Two things this guide will not tell you, because they are not settled.
First, whether a party wall award binds a later owner is unresolved. The Act defines a building owner as an owner of land “who is desirous of exercising rights under this Act”, says nothing about successors in title, and contains no mechanism for assigning an award. Published commentary notes the issue “does not appear to have been tested in court”. Treat anyone who tells you the answer confidently with caution.
Second, no mechanism was found for registering an award against the property — not in the Act, not in the Land Registry’s guidance on protecting third party interests, and not in the classes of registrable land charge. That is a search that came back empty rather than a statement that it can never be done.
Government guidance on selling is notably thin, and predates all of this: asked whether a seller must tell a purchaser about a notice or dispute, it says only that property information forms “may include questions on the Act including whether there has been a dispute”.
A dating point worth knowing. That government booklet was first published on 12 May 2016 and has never been substantively updated. It therefore predates Power v Shah by nearly seven years and does not mention it. Where the booklet and the Court of Appeal address the same question, the case governs.
What to do next
If work has started next door and you have had no notice, the practical sequence is: tell them in writing that you believe the Act applies, record the condition of your property now, take legal advice before threatening or starting proceedings, and understand that a surveyor cannot award you anything if no notice was served.
If you are the building owner and have not yet started, serve the right notice. The party wall notice guide covers which one and when, and the what the Act calls an award guide explains the document that follows a dispute. The guide to whether a surveyor is needed at all covers the prior question, and the Party Wall surveyor guide explains the role. Others are listed in the guides index.
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If you need quotes for a notice served properly, you can post your Party Wall job — free. An administrator reviews each request and could invite suitable surveyors when the comparison service is available.
A note on sources
Power v Shah [2023] EWCA Civ 239 was read in full from the approved judgment published by the National Archives. Statutory provisions are taken from the revised text of the Act on legislation.gov.uk. Passages described as government guidance come from the GOV.UK explanatory booklet, which states that it cannot provide a definitive interpretation of the law. Cases discussed inside the Court of Appeal’s judgment are described as the court described them, not read separately. The Act extends to England and Wales only, by section 22(4).