If you are extending or converting a loft in a semi or terrace, or building close to your boundary, the Party Wall etc. Act 1996 almost certainly applies. It is not complicated, but the notice periods are long, so it is worth starting early.
The Act exists to let you carry out work near your neighbour's property while protecting them from damage. It does not give a neighbour the power to stop your project. It sets out how the work is agreed and recorded.
When the Act applies
There are three situations.
1. Work to a party wall
A party wall is a wall shared with a neighbour, such as the dividing wall of a semi or terrace. Notifiable work includes cutting into it to take the end of a steel beam, raising it, thickening it, or cutting in flashings. Most loft conversions in semis and terraces fall under this, because the new steels usually bear on the party wall, and a hip-to-gable conversion often raises it.
2. Building a new wall on or at the boundary
If you are building a new wall on the boundary line, or right up against it, you need to notify your neighbour first. This comes up often with side and rear extensions.
3. Digging foundations near a neighbour's building
If you are excavating within 3 metres of a neighbour's building and going deeper than their foundations, or within 6 metres where the dig cuts a 45-degree line down from their foundations, the Act applies. Many rear extension foundations are affected.
The notices and how early to serve them
| Notice | Used for | Minimum notice |
|---|---|---|
| Party structure notice | Work to an existing party wall | 2 months |
| Line of junction notice | A new wall on or at the boundary | 1 month |
| Notice of adjacent excavation | Foundations near a neighbour's building | 1 month |
A notice must describe the work and when it will start. Once served, it stays valid for a year. You can serve it yourself or have a surveyor do it, and you can start sooner than the minimum period if your neighbour agrees in writing.
What your neighbour can do
Your neighbour has 14 days to respond. They can:
- Consent in writing. The work goes ahead. Many people still agree a schedule of condition, a dated record with photos of the neighbour's property before work starts, which protects both sides.
- Dissent, or not reply at all. Either way a dispute is treated as having arisen. That sounds worse than it is: it simply means surveyors are appointed.
If surveyors are appointed
You and your neighbour can agree on a single surveyor, or each appoint your own. The surveyors prepare a party wall award, a document that sets out what work will be done, how and when, and records the condition of the neighbour's property. It also covers access and working hours where relevant.
The person carrying out the work normally pays the surveyors' reasonable fees. Costs vary with the job and whether one or two surveyors are involved, but they are commonly in the region of £800 to £1,500 per neighbour where a surveyor is needed. It is a line worth including in your budget from the start.
How to keep it simple
- Talk to your neighbours first. A conversation before the paperwork arrives makes consent far more likely.
- Serve early. Once the design is settled, serve the notices so the timing does not hold up the start date.
- Offer a schedule of condition even if they consent. It avoids arguments about old cracks later.
- Keep them informed during the build, especially before noisy or messy days.
How it fits the programme
The two-month notice for party structure work is the one that most often affects start dates, so we flag it on the first visit and build it into the timeline alongside drawings and planning. See how long an extension takes for the full sequence.
This is general guidance. For anything beyond a straightforward case, a party wall surveyor is the right person to advise. Read more about our extensions and loft conversions.
Common questions
Is the Party Wall Act part of planning permission?
No. It is a separate civil law between neighbours. Getting planning permission or building under permitted development does not remove your duties under the Party Wall Act, and the council does not enforce it.
Can my neighbour stop my extension using the Party Wall Act?
No. The Act does not give a neighbour a veto. It sets out how the work is done, protects their property and, if there is a dispute, lets surveyors settle the details in an award.
Who pays the party wall surveyor?
Normally the person doing the work pays the reasonable costs of the surveyors, including the neighbour's surveyor if they appoint their own.
How long is a party wall notice valid?
A year. If the work has not started within a year of the notice being served, it has to be served again.
General guidance for homeowners in England, written in September 2026. Rules, fees and prices change, and every house is different, so we confirm everything for your property on the free site visit.
