The short answer
You need to follow the Party Wall etc. Act 1996 if your work falls into one of three categories: work on an existing shared (party) wall or structure, such as cutting in steel for a loft conversion or removing a chimney breast on the shared wall; building a new wall on or astride the boundary with a neighbour; or excavating within 3 metres (and sometimes 6 metres) of a neighbouring building where you dig deeper than their foundations — typical of extensions and basements. If your project does one of these, you must serve notice. Many common jobs are not notifiable, including most purely internal work that does not touch the party wall, such as replastering your own side or fitting kitchen units. If in doubt, a surveyor can confirm whether the Act applies before you serve anything. This is general guidance, not legal advice.
The Act is triggered by the type of work, not by whether you get on with your neighbour. The lists below cover the work that is notifiable and the jobs that usually are not, so you can place your project before paying for anything.
Notifiable or not?
- Work on the shared wallnotifiable
- Building on the boundarynotifiable
- Digging near foundationsnotifiable (3–6 m rule)
- Internal work, own sideusually not
- Still unsureask a surveyor
Work that is notifiable
- On a party wall: cutting in beams for a loft conversion, removing a chimney breast on the shared wall, inserting a damp-proof course, raising or thickening the wall.
- New boundary wall: building a new wall on, or astride, the line of junction with the neighbouring property.
- Excavation: digging foundations within 3 metres of a neighbour's structure and deeper than their foundations, or within 6 metres where your dig could undercut a line drawn down at 45 degrees from theirs — common with extensions and basements.
| Project | Usually notifiable? |
|---|---|
| Loft conversion with steels in the party wall | Yes |
| Removing a shared-wall chimney breast | Yes |
| Rear/side extension with foundations near a neighbour | Yes (excavation rule) |
| New wall built on the boundary | Yes |
| Replastering or decorating your own side | No |
| Fitting kitchen units or a new bathroom | No |
General guidance — confirm your own case. Source: GOV.UK party walls overview and explanatory booklet.
Common jobs that usually are not
A lot of home improvement does not engage the Act. Purely internal work on your own side that does not affect the shared structure — replastering, decorating, fitting units, putting up shelves, or a new bathroom or kitchen — is normally not notifiable. Small jobs such as fixing flashing or drilling to add wall plugs are typically too minor to count. The line is whether you are working on the shared wall itself, building on the boundary, or excavating near a neighbour's foundations. If your project is clearly internal and away from the party wall, you usually do not need an agreement — but where it is borderline, confirming with a surveyor first is cheaper than getting it wrong.
Not sure if the Act applies to you?
We'll match you with a vetted party wall surveyor who reviews your plans, confirms whether your work is notifiable, and only serves notices if you actually need them.
Frequently asked questions
Do I need a party wall agreement for a loft conversion?
Usually yes, if the work involves the shared party wall — for example cutting in steel beams or removing a chimney breast on that wall. That is notifiable under the Act, so you serve notice. A surveyor can confirm based on your drawings.
Do I need a party wall agreement for an extension?
Often yes, because of the excavation rule: if your foundations are within 3 metres of a neighbour's structure and dug deeper than theirs (or within 6 metres in some cases), it is notifiable. A surveyor can check the distances against your plans.
When do I not need a party wall agreement?
Most purely internal work on your own side that does not touch the shared wall — replastering, decorating, fitting kitchen or bathroom units — is not notifiable. The Act is triggered by work on the party wall, building on the boundary, or excavating near a neighbour's foundations.
Sources & further reading
- GOV.UK — party walls and building work: overview
- GOV.UK — the Party Wall etc. Act 1996: explanatory booklet
Figures on this page are typical UK ranges drawn from published sources and depend on your specific project. They are guidance, not a quotation, and not legal advice.