My neighbour started building without a party wall notice

Last updated: 30 July 2026

The short version: if the work needed a notice and none was served, your neighbour has skipped a legal duty — and courts have both stopped such work and awarded damages. But before anything else, it's worth checking the work really was notifiable, because plenty of building work isn't.

First: did the work actually need a notice?

The Act covers three families of work: cutting into or altering a shared wall or structure (steel beams for a loft, removing a chimney breast, raising the wall); building a new wall at or astride the boundary; and digging within 3 or 6 metres of your building, deep enough to matter — the 3-metre and 6-metre rules explained.

Plenty of work touches none of these. Plastering, rewiring, new sockets and shelving on their side of the wall need no notice at all. An extension built clear of the boundary with shallow foundations may not either. So the first honest step is the free party wall check — answer as if you were them, and see whether their project was notifiable at all.

Also worth ruling out the mundane: notices go astray. Before assuming bad faith, ask them. "Did you serve a party wall notice for this?" is a fair question, and many building owners have simply never heard of the Act.

How much notice should they have given?

Useful for working out whether they're actually late, or whether you simply haven't received the letter yet. The periods are fixed:

• Two months before work on a shared wall or structure — beams into the party wall, raising it, cutting away a chimney breast.
• One month before a new wall at the boundary, or excavation within 3 metres (or 6 metres for deeper digs) of your building.

So if the scaffolding went up last week and nothing arrived two months ago, a section 2 notice was owed and is late. One more thing to check before you conclude anything: a notice stays valid for 12 months, so a letter from three years ago about work starting now has lapsed and should have been served again.

"But they've got planning permission"

The most common thing a neighbour says at this point, and it doesn't answer the question. Planning permission, Building Regulations approval and party wall notices are three separate systems. Having one grants nothing under the others. A council approving the design says nothing about whether your neighbour was entitled to cut into a wall you share, and Building Control signing off the steels doesn't mean you were notified. Nobody at the council was ever asked to consider you.

Is it illegal? Not criminal — but it is a real legal exposure

There's no fine and no prosecution written into the Act for skipping a notice — it leaves this as a civil matter between the two of you. That sounds toothless. It isn't:

• Courts have stopped un-notified work by injunction and awarded damages under ordinary law — the leading case is Louis v Sadiq (1996). Starting notifiable work without notice exposes the builder to exactly that.
• The Act's own machinery can't be patched in afterwards: the Court of Appeal held that where no valid notice exists, a party wall award is void — Power & Kyson v Shah (2023). Your neighbour can't quietly tidy the paperwork later and carry on as if the Act had been followed.

In plain terms: by not serving notice, your neighbour gave up the Act's orderly process and took on court-shaped risk instead. That's leverage — best used calmly.

The sensible first moves

Document, immediately. Dated photos of your walls, ceilings and anything already cracked or altered — inside and out. This is the same principle as the schedule of condition surveyors prepare: a dated record is the evidence that settles arguments about what was damage and what was always there.

That term is worth knowing by name. A schedule of condition is a dated written and photographic record of a property before work starts, and it's the single most useful document in any party wall argument — because the fight is almost never about the law, it's about whether a crack is new. It isn't required by the Act, and in your situation no surveyor has been appointed to prepare one, so an amateur version taken by you today is far better than a professional one that never existed. Photograph rooms wide, then close on every existing defect, and don't crop anything.

Put it in writing. A short, civil note to your neighbour: you believe the work needed a party wall notice, none was received, and you'd like them to pause and put it right. Keep a copy.

Take advice early. If the work is still going and it plainly affects your property, speak to a party wall surveyor or a solicitor promptly — an injunction is a court matter, timing matters, and this page can't judge your exact facts. What we can say is that the law here is on the side of the person who should have been served.

Be realistic about an injunction

It's the remedy everyone reaches for, and it's real — courts have stopped un-notified work. But it's worth setting expectations honestly, because the "leverage" framing can mislead.

An injunction is a court application, with the cost and timetable that implies, and the works that trigger these disputes are often short. Beams go in over a few days; a chimney breast comes out in one. There's a real risk of spending significantly to stop something that finishes first — and if you lose, costs can follow. That's not a reason not to take advice; it's a reason to take it quickly, while stopping the work is still a meaningful outcome rather than a symbolic one.

In many cases the better route is the one that survives the works finishing: a documented record now, and a compensation claim later if damage appears.

If damage has already happened

Photograph it, date it, and don't accept a cash-and-a-handshake fix before you've had advice. Where notifiable work proceeded without notice, damages claims run through the ordinary courts (Louis v Sadiq again) rather than the Act's tidier compensation route — one more reason the notice your neighbour skipped existed to protect you both.

The trap: you can't use the Act's process either

This is the part almost nobody states, and it's the most important thing on the page. It's tempting to think that if your neighbour skipped the notice, you can simply appoint a surveyor and force the Act's machinery to start. You can't.

The Court of Appeal has held that without a valid notice the Act's dispute procedure is not engaged at all, and an award produced anyway is void. The machinery cuts both ways: it protects you when a notice is served, and it's simply unavailable to either of you when one isn't. So a surveyor who offers to draw up an award to "regularise" the works is offering something the Act doesn't recognise.

What that leaves you is the ordinary courts — which is a slower and more expensive route, and exactly why the missing notice matters. It also means your claim isn't limited by the Act's framework, and the compensation route it would have offered isn't the ceiling. Take advice on which is better in your case; don't assume the absence of an award means the absence of a remedy.

What if it's never resolved and they sell?

It doesn't quietly disappear at the point they move. When your neighbour sells, the standard conveyancing form asks the seller directly whether they're aware of any notice served or received under the Act, and about works carried out — so an un-notified job is a question their buyer's solicitor may well end up asking about.

Two practical consequences. Your dated photographs stay useful, because the new owner inherits the building but not your memory of what it looked like before. And if you're the one buying next to works like these, or selling with them in your own history, selling a house with no party wall agreement covers what gets disclosed and what insurance does and doesn't fix.

If you want to check what your neighbour was actually required to do, and when, the Act explained in full lays out every duty and clock in one place.

Wondering whether the paperwork can simply be sorted out after the fact? Short answer: not under the Act — retrospective party wall agreements, honestly explained. And if you received a notice after all, start here: what your party wall notice means.