The notices you may receive
| What they are building | Notice you may get |
|---|---|
| A wall on the boundary line | Line of junction (section 1) |
| Foundations within 3 m of your house, deeper than yours | Adjacent excavation (section 6) |
| Steel or a flashing into the shared wall | Party structure (section 3) |
On the boundary
They can ask to build the new wall astride the boundary, but only you can agree to that. If you do not, it must go wholly on their land, although its footings can project under yours where necessary. You are entitled to compensation for any damage.
Foundations near your house
Digging close to your foundations is where most of the risk lies. You can insist your foundations are underpinned or otherwise protected where that is needed, and a surveyor will check the method.
Living with the work
Expect noise, dust and deliveries for several months. See living next to building work.
Before you reply
Photograph the back of your house, the boundary and any cracks inside near the shared wall, then decide how to respond.
Common questions
Can I object to the size of their extension?
Not through the Party Wall Act. Size and appearance are planning matters.
Where this comes from in the Act
- Section 1: New building on line of junction
- Section 6: Adjacent excavation and construction
- Section 7: Compensation etc.
Links go to the official text of the Party Wall etc. Act 1996 on legislation.gov.uk.