Almost every London terrace, mansion block and semi shares a wall with somebody, which is why the Party Wall etc. Act 1996 catches so many interior projects that look, on paper, like nothing to do with the neighbours. Cut a pocket into the shared wall to seat a steel above a new opening and you are in it. Take out a chimney breast on that wall and you are in it. Dig new foundations for a rear extension deeper than next door's and you are in it.
None of that is a problem. The Act is a procedure, not a veto, and a neighbour cannot use it to stop work they simply dislike. What it can do is add two months to a programme that nobody costed for, which is why it belongs in the design timeline rather than in the builder's first week.
What triggers a notice, and how long each takes
| Section | Typical work | Notice |
|---|---|---|
| Section 1 | A new wall built up to or astride the boundary | 1 month |
| Section 2 | Cutting into the party wall for a beam, removing a chimney breast, underpinning, a full-thickness damp proof course, raising or extending the wall, cutting off projections | 2 months |
| Section 6 | Excavating within 3 metres and below the neighbour's foundations, or within 6 metres and below a 45 degree line from them | 1 month |
A notice is only valid for a year. Serve it too early and it expires before you break ground; serve it too late and you wait. On a typical London refurbishment the sensible moment is once the structural design is settled and before you tender, because the notice has to describe the works accurately.
Interior work that usually does trigger it
- Cutting into a party wall to take the bearing of a new beam, which covers most open-plan reconfigurations and side-return extensions.
- Removing a chimney breast where the stack sits in the party wall.
- Underpinning, including for a basement or a lowered ground floor.
- Inserting a damp proof course through the whole thickness of a party wall.
- Raising the height of a party wall, common in loft conversions, or extending it downwards.
- Demolishing and rebuilding a party wall, or cutting off projections such as old corbels or a flue haunch.
Interior work that usually does not
- Replastering, redecorating and new joinery.
- A new kitchen or bathroom in the same position, with no structural change.
- Moving or building non-structural stud partitions away from the party wall.
- Fixing shelves, sockets, kitchen units and radiators to a party wall. Minor fixings are not notifiable, though there is no bright line in the Act and heavy-duty resin anchors into a shared wall are worth a conversation.
- Replacing floor coverings, unless the joists bear into the party wall and are being altered.
If you are unsure, the test to hold in your head is simple: are you doing something to the shared structure, or just to your own surfaces?
Serving the notice
You serve it yourself or through a surveyor, in writing, on every adjoining owner. In a leasehold block that means the freeholder and any leaseholder with more than a year left on their term, which in a converted London house is usually three or four people rather than one.
The notice has to name the building owner, describe the proposed works, and give the date they are intended to begin. Send drawings with it even though the Act does not demand them. A neighbour who can see what you are actually doing consents far more often than one handed a paragraph of statutory language.
The 14 day rule, and why projects slip here
The adjoining owner has three options: consent, dissent and appoint their own surveyor, or dissent and agree to a single surveyor acting for both. If 14 days pass from service and they have done nothing at all, a dispute is deemed to have arisen. Not consent. A dispute.
Once that happens you cannot start until surveyors are appointed and an award is made. Clients who assume silence means agreement lose the whole notice period and then the award period on top. If nothing has arrived by day ten, knock on the door.
Surveyors and the award
Where a dispute is deemed or declared, either both owners appoint one agreed surveyor between them, or each appoints their own and those two select a third surveyor to resolve any deadlock. The agreed surveyor route is faster and materially cheaper, and there is nothing improper about proposing it in your covering letter.
What the surveyors produce is a party wall award: the works permitted, how and when they may be carried out, a schedule of condition recording the neighbour's property before you start, and who pays for what. The schedule of condition is the part that protects you. Without it, every pre-existing crack next door becomes your problem in six months' time.
The building owner normally pays all the costs, including the adjoining owner's surveyor. Where the work is needed because of a defect or a repair benefiting both properties, costs can be shared. Each owner then has 14 days from service of the award to appeal to the county court, which is rare and expensive.
Where it sits in a London programme
Party wall is one of four consents that catch London interiors, and they run on different clocks. Treat them as parallel workstreams from the design stage:
- Party Wall Act notice: one to two months, plus award time if disputed.
- Licence to alter: freeholder consent in a leasehold flat, often the slowest of the four.
- Listed building consent: needed for interior work in a listed building, and a criminal offence to skip.
- Building regulations: structural openings, insulation, fire separation and ventilation, via building control.
Started in the right order these overlap and cost you nothing in time. Started when the builder arrives, they stack, and a three month refurbishment becomes a six month one. Our project timeline guide sets out where each of them lands.
Practical points that save money
- Talk before you serve. A notice arriving cold reads as a threat. A conversation first turns most dissents into consents.
- Propose an agreed surveyor. One fee rather than two, and one set of correspondence.
- Get the schedule of condition done properly, with photographs, even where the neighbour consents and no award is required.
- Do not let the contractor serve it. The notice must come from the building owner, and an invalid notice is worth nothing if it is challenged later.
- Remember it is England and Wales only. There is no equivalent statutory regime in Scotland.
Handled early, the Act is paperwork. Handled late, it is the reason your kitchen is a building site in December.
Frequently Asked Questions
Do I need a party wall notice for interior work?
Only if the work touches the party wall itself or goes below your neighbour's foundations. Cutting in a steel to take the bearing of a beam, removing a chimney breast on a shared wall, underpinning, inserting a damp proof course through the full thickness, raising or extending the wall, or cutting off projections all require a party structure notice. Replastering, a new kitchen, moving a stud partition or fixing shelves do not.
How much notice do I have to give my neighbour?
Two months for works to an existing party wall or structure under section 2. One month for building a new wall up to or astride the boundary under section 1, and one month for excavation under section 6. A notice stays valid for a year, so you cannot serve it in January and start the following spring.
What happens if my neighbour ignores the party wall notice?
Silence is not consent. If nothing has come back 14 days after service, a dispute is deemed to have arisen and surveyors have to be appointed before you can start. This is the single most common reason a London renovation slips: the client assumes no reply means everything is fine, and loses six weeks discovering otherwise.
What is the 3 metre and 6 metre rule?
Section 6 catches excavation in two situations. Within 3 metres of a neighbouring building, where you dig deeper than the bottom of their foundations. And within 6 metres, where your excavation would cut a line drawn down at 45 degrees from the bottom of their foundations. Both need one month's notice. Basement digs and most rear extension foundations in London trigger one or the other.
Who pays for the party wall surveyor?
Normally the building owner doing the work, including the adjoining owner's surveyor. The exception is where the work is needed because of a defect or a repair that benefits both properties, in which case costs can be shared. Appointing a single agreed surveyor rather than one each is the cheapest route and is worth proposing in the covering letter.
Does the Party Wall Act apply to flats?
Yes. The wall between two flats and the floor between them can both be party structures, and leaseholders with a term of more than a year count as owners under the Act. In a block you will usually need a party wall notice and a licence to alter from the freeholder, and they are separate processes with separate timescales that should run in parallel.
Sources
- Ministry of Housing, Communities and Local Government, The Party Wall etc. Act 1996: explanatory booklet: gov.uk
- Party Wall etc. Act 1996: legislation.gov.uk
This guide explains the statutory procedure and is not legal advice. Checked against the government's explanatory booklet on 18 August 2026.