What does a party wall agreement cost?
Short version: serving the notice yourself is free, and if your neighbour consents that's usually the end of it. Costs only appear if they dissent and surveyors get involved — and the building owner pays both sides.
£0if your neighbour consents — most do
£1,575–£3,375if they dissent · one shared surveyor, by project
£1,800–£5,400if they dissent · a surveyor each
Step by step: where money can appear
| Stage | Typical cost | Worth knowing |
|---|---|---|
| Serving the notice yourself | Free | Just postage. Our free checker tells you which notice you need. |
| A ready-to-serve notice pack | £39 | Pre-filled notices from the official templates, your neighbours' reply forms, and serving guides. |
| A firm drafting & serving for you | £150–£400 | The traditional route the pack replaces. |
| Your neighbour consents in writing | £0 further | Most cases end here. Keep the consent letter. |
| They dissent → one “agreed surveyor” | ≈£1,000–£3,375 | One impartial surveyor for both sides — usually the cheaper dissent route. See the project table below. |
| They dissent → a surveyor each | £1,800–£5,400 | Each side appoints their own; the building owner normally pays both. |
If surveyors are appointed: typical totals by project
Published 2026 averages for a single agreed surveyor:
| Project | Typical total |
|---|---|
| Loft conversion | ≈£1,575 |
| Rear or side extension | ≈£2,025 |
| New build | ≈£2,475 |
| Basement | ≈£3,375 — and always a case for professional advice from day one |
Surveyors themselves charge roughly £90–£450 an hour (£150–£200 is typical). London: £750–£1,800 per neighbour is commonly quoted, so multi-neighbour London projects add up fastest.
Who pays what — it's in the Act, not up for debate
| Cost | Who pays |
|---|---|
| The building work itself | Building owner |
| The neighbour's reasonable surveyor fees | Building owner — the neighbour's protection is free to them |
| Extra works the neighbour asks for (counter-notice) | The neighbour, for that extra work |
| Work fixing a defect the neighbour is responsible for | Shared — the neighbour contributes |
| Using a wall later that the builder paid for ("enclosing on") | The neighbour contributes then |
More detail on how the process plays out is in our guides, and if a neighbour has served you a notice, start with what it means for you — responding costs you nothing.