Party wall surveyor for extensions
Rear, side and wraparound extensions can need Section 1, 2 and 6 notices. Here's how to tell.
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In short
A rear or side extension needs notice if you build a new wall on or up to the boundary (Section 1, 1 month), do work to the party wall such as cutting in a flashing (Section 2, 2 months), or dig foundations within 3 m of the neighbour's house that go deeper than theirs (Section 6, 1 month). Many extensions trigger two or three sections at once.
Which sections apply
| Extension feature | Section |
|---|---|
| Flank wall built on or up to the boundary | Section 1 |
| Foundations within 3 m of the neighbour, deeper than theirs | Section 6 |
| Flashing cut into the neighbour's wall, or raising a shared wall | Section 2 |
| Steel beam bearing on the party wall when knocking through | Section 2 |
Back-to-back extensions
On Manchester terraces, neighbours often both extend. If the neighbour already has an extension on the boundary, using their wall or building against it changes which notices you need. We check what's already there.
Two-storey extensions
Two-storey side and rear extensions are more likely to need Section 6 notices for deeper foundations, and sometimes trial holes to confirm the neighbour's footing depth.
Common questions
Do I need a party wall agreement for a single-storey rear extension?
Often yes, because the foundations are usually within 3 m of the neighbour and deeper than their footings, and the side wall may be on the boundary.
Can my builder serve the notice?
Anyone can serve notice for you, but it must be accurate. We often work alongside builders and architects to get notices out early.
Source: Party Wall etc. Act 1996 (applies in England and Wales).
Written by Guy Crouch BSc (Hons) MRICS, Director and Chartered Building Surveyor at Manchester Party Wall Surveyors. Last reviewed 26 October 2026. This page is general guidance, not legal advice. About our team
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