Party wall agreements explained
When you need one, how it works and what it costs
A party wall agreement is a written agreement with your neighbour, under the Party Wall etc. Act 1996, before you build on or next to a wall you share, or dig close to their foundations. You serve a notice at least one month before (two months for work to the shared wall itself). If the neighbour agrees in writing, you are done. If they do not, surveyors settle it. It is separate from planning permission and from Building Regulations, and the surveyor's fee is not in our guide prices.
When you need one
It applies in England and Wales. There are three kinds of notice:
| Your project | Usually | The rule |
|---|---|---|
| Cutting in beams, or raising or rebuilding a shared wall | Party structure notice | At least 2 months before work starts. Common for loft steels and for opening up the back of a terrace or semi. |
| Building a new wall on, or against, the boundary | Line of junction notice | At least 1 month before work starts. |
| Digging within 3 m of a neighbour's building and deeper than its foundations (or within 6 m, in some cases) | Adjacent excavation notice | At least 1 month before work starts. Common for deeper foundations and basements. |
What happens, step by step
1. Serve the notice
In writing, to every neighbour affected, with a description of the work. We can help you prepare it, and a party wall surveyor can serve it for you.
2. The neighbour has 14 days to respond
They can consent. If they say nothing, or do not agree to the terms within the time, it counts as a dispute and surveyors are appointed.
3. Surveyors, if there is a dispute
The neighbours can agree on one surveyor, or each appoint their own. They write an "award": the work allowed, when and how, and a record of the condition of the neighbour's property before you start.
4. Build
You build to the award. The record of condition protects both sides if a crack appears later.
Can my neighbour stop my extension?
No. The Act does not give a neighbour a veto over work you are entitled to do. It lets them have it done properly, with conditions such as protecting their property, working hours, and a record of its condition. A neighbour can, however, delay things if they dispute the notice, which is why we serve it early and keep the relationship friendly.
What it costs
If a neighbour consents, you pay almost nothing beyond the notices. If surveyors are appointed, the building owner usually pays their reasonable fees, for your neighbour's surveyor as well as your own. Commonly quoted fees run from several hundred to a couple of thousand pounds per neighbour, and more for complicated work. The surveyor's fee is not included in our guide prices, and we say so in the calculator: "party wall surveyor (often or typically required)".
What it does not cover
A party wall agreement is not planning permission, and it is not Building Regulations approval. You need those too, where they apply: see our planning guides for extensions and lofts. Nor does it deal with a neighbour's right to light, which is a separate matter.
The same figures as our cost calculator, for the building work at a mid-range finish. They are guide prices while our launch pricing is finalised; your exact price follows a free survey. General guidance, not legal advice.
Common questions
What is a party wall agreement?
A party wall agreement is a written agreement with your neighbour, under the Party Wall etc. Act 1996, before you build on or next to a wall you share, or dig close to their foundations. You serve a notice at least one month before (two months for work to the shared wall itself). If the neighbour agrees in writing, you are done. If they do not, surveyors settle it. It is separate from planning permission and from Building Regulations, and the surveyor's fee is not in our guide prices.
Do I need a party wall agreement for a loft conversion or an extension?
Usually, yes, on a terrace or a semi, because the steels sit in the shared wall or the foundations go near a neighbour. A detached house may need one for work near the boundary or deeper foundations.
How much does a party wall agreement cost?
If the neighbour consents, very little. If surveyors are appointed, commonly from several hundred to a couple of thousand pounds per neighbour, usually paid by the person building. Not included in our guide prices.
How long does a party wall agreement take?
Serve notice at least 1 month before work for new boundary walls and excavation, and 2 months for work to the shared wall. A neighbour has 14 days to reply. A dispute and an award can add several weeks.
What if my neighbour does not agree?
Surveyors settle it. The neighbour cannot stop the work, but the award sets conditions and records the state of their property first.
Is a party wall agreement the same as planning permission?
No. It deals with your neighbour's property rights. Planning and Building Regulations are separate.
How do I get an exact price for the building work?
Book a free survey. We will tell you which notices your job needs.