The neighbours either side
In a terrace, a loft conversion often affects both party walls, so both neighbours need notice. In a semi-detached house, it is usually only the attached neighbour, unless digging on the other side brings the excavation rules into play.
The property behind
A rear extension can bring you within 3 or 6 metres of a building at the back, such as a garage, an outbuilding or the house behind. If the excavation rules are met, that owner is an adjoining owner too.
Further away, under the excavation rules
The Act treats the owner of any building or structure within the 3 or 6 metre distances as an adjoining owner for that excavation. A deep basement can therefore catch a neighbour two doors down. Our sister site explains the 3 and 6 metre rules.
Buildings split into flats
Everyone who counts as an owner of an affected part needs notice. That usually means the freeholder and the long leaseholders of flats next to the work, but not tenants on short lets. See absent owners and landlords and councils and housing associations.
Some typical examples
| Project | Who usually needs notice |
|---|---|
| Loft conversion, mid-terrace | The owners on both sides |
| Loft conversion, semi-detached | The attached neighbour |
| Rear extension on the boundary of a semi | The attached neighbour, plus any building behind if foundations go within 3 metres and below its footings |
| Basement in a terrace | Both neighbours, and possibly owners further along under the 6-metre rule |
When in doubt, serve
A notice served on someone who turns out not to be affected costs little. Missing an owner who is affected can leave part of your work without the Act's protection.
Common questions
My neighbour rents their house out. Who do I serve?
The landlord, as owner. You can also let the tenants know as a courtesy, but they cannot consent for the owner.
Do I need to serve the owner of a garage at the end of my garden?
Only if the work affects it, for example if you dig within 3 metres of it and below its foundations.
Where this comes from in the Act
Links go to the official text of the Party Wall etc. Act 1996 on legislation.gov.uk.