When do I need a party wall agreement?

Short answer

In England and Wales you must serve notice on your neighbour before working on a shared wall, building on the boundary line, or digging foundations within 3 metres (sometimes 6 metres) of their building. Notice periods are one or two months. Scotland and Northern Ireland have no Party Wall Act.

What counts as party wall work?

Cutting into a shared wall to insert a steel beam, as in many loft conversions and knock-throughs.
Building a new wall on or astride the boundary.
Excavating within 3 m of a neighbour’s building and deeper than its foundations, or within 6 m in some cases.

Notice periods

One month’s notice for building on the line of junction and for excavation, and two months for work to an existing party wall. The neighbour can consent in writing or dissent, in which case surveyors are appointed.

What does a party wall surveyor do?

If your neighbour dissents, an agreed surveyor (or one each) prepares a party wall award. It records the condition of the neighbour’s property and sets out how the work will be done. The building owner normally pays the surveyors’ reasonable fees.

Scotland and Northern Ireland

There is no equivalent act. Rights over shared walls come from title deeds, the Tenements (Scotland) Act 2004 for flats in Scotland, and common law. We still agree arrangements with neighbours in writing.

How we handle it

We identify party wall work at the design stage, prepare the notices and drawings, and build the timescale into the programme so it does not delay the start.

Sources and further reading

This guide is general information, not legal or tax advice. Rules change and depend on your property; we confirm what applies to your project at the survey.