Extensions
Extension Party Wall Notice
A rear extension on a terraced house often raises two questions at once: work to the party wall, and new foundations close to the neighbour. They can require different notices. We do not collapse them into one generic letter.
General information. Status: pending project-specific review by a qualified Party Wall professional. House-style review 27 September 2026.
- Rear extensions close to a shared wall
- Side-return extensions towards a boundary
- Wraparound extensions, which often affect more than one neighbour
- New walls built up to or astride the boundary line
Foundation depth matters. An adjacent excavation notice is usually served at least one month before excavation, as a general rule, where the Act’s distance and depth tests are met. Those tests are applied by a professional to the engineer’s drawing, not by this page.
If two neighbours are affected, the fee is not the same as for one. Our from-prices are per adjoining owner for notice work. Flats above either house can add further people who need to be considered.