Not every extension needs Party Wall procedures, but some building work in England and Wales falls within the Party Wall etc. Act 1996 and requires formal notice to adjoining owners.
The Act can apply to work on an existing party wall or structure, building on or near the boundary, and certain excavations close to neighbouring buildings.
What kind of extension work can trigger Party Wall procedures?
Examples can include:
- cutting into a party wall to insert beams or other structural elements;
- raising, rebuilding or otherwise working on a party wall;
- building a new wall on or at the boundary;
- excavating below and near the foundation level of a neighbouring building.
The exact position depends on the proposed work and the relationship between the properties, so it should be checked rather than assumed.
Is a Party Wall Agreement the same as planning permission?
No. Party Wall procedures are separate from planning permission and Building Regulations. A project can have planning permission and still need Party Wall notices, or it can be permitted development and still fall within the Act.
When do neighbours need to be told?
Government guidance says notice must be served before work covered by the Act begins. The notice period depends on the type of work: party-structure work generally requires at least two months’ notice, while some boundary and excavation notices use a one-month period.
Official guidance: GOV.UK Party walls and building work.
What happens after notice is served?
An adjoining owner can consent in writing, or a dispute can arise and the Act’s surveyor process can apply. No response does not simply mean automatic consent for the relevant notices.
Do you always need a Party Wall surveyor?
No. If the work is covered by the Act and the adjoining owner consents properly in writing, a surveyor may not be required. If there is a dispute, the statutory surveyor process becomes relevant.
When should you check the Party Wall position?
Early enough that the notice period and any surveyor process can sit sensibly alongside the construction programme. It is usually better to identify the issue during technical development than a few days before a builder wants to start excavating or inserting steelwork.
For extensions, Party Wall considerations often sit alongside structural engineering and Building Regulations.
The simple version
An extension does not automatically require a Party Wall Agreement, but certain boundary, party-wall and excavation work can bring the Party Wall etc. Act 1996 into play.
If your design is close to a neighbour, changes a shared wall or needs significant excavation, the Party Wall position should be checked before construction starts.
This article is general guidance for England and Wales and is not a substitute for advice from a suitably qualified Party Wall surveyor or legal adviser.