Here’s a practical summary of when you must serve notice—and when you don’t.
When You Must Serve a Party Wall Notice
You are legally required to serve notice on your neighbour (the adjoining owner) if you plan to carry out any of the following types of work:
1. Building on the Line of Junction
- Constructing a new wall on or astride the boundary between your property and your neighbour’s (known as the line of junction).
- Building a new party wall that sits directly on the boundary line (with your neighbour’s consent).
- If no consent is given, you must build the wall entirely on your own land.
2. Work Directly to a Party Wall or Party Fence Wall
Examples include:
- Underpinning
- Thickening the wall (e.g. adding insulation and plasterboard)
- Structural repairs
- Demolishing and rebuilding
- Increasing or reducing height (but not below 2m)
- Cutting into the wall for any purpose (e.g. installing a beam or damp proof course)
- Removing chimney breasts or other projections on your side
- Inserting flashing where your new wall adjoins your neighbour’s
- Tying a new building into the party wall
- Rebuilding or raising a party fence wall for use as part of a new structure
- Exposing the party wall (for example, if replacing a roof or structure that previously protected it)
Note: Some actions—such as cutting into a party fence wall—are excluded from certain provisions of the Act.
3. Excavation Close to a Neighbour’s Building
You must serve notice if you are:
- Excavating within 3 metres of a neighbouring structure and your dig goes deeper than your neighbour’s foundations.
- Excavating between 3 to 6 metres from their structure and your excavation intersects a 45-degree line drawn down from the base of their foundations.
When You Do Not Need to Serve a Notice
You do not need to serve notice under the Act if:
- You are building a wall fully on your own land, even if it’s near the boundary, provided your excavation doesn’t go deeper than your neighbour’s foundations.
- You are converting a basement and installing a new floor, as long as you don’t cut into or excavate below the party wall or neighbouring foundations.
- You are erecting a timber or concrete post fence on your land (not encroaching on your neighbour’s land).
- You are painting or decorating your own fence or jointly owned fence.
- You are widening a chimney breast opening without cutting into the party wall.
- You are removing an internal wall but leaving a pier that supports the party wall.
- You are excavating up to, but not deeper than, your neighbour’s foundations.
Conclusion: When in Doubt, Don’t Guess
Ignoring the Party Wall Act can lead to serious consequences—delays, legal action, and costly disputes. If you’re unsure whether your work is notifiable, it’s always best to seek professional advice first.
Need Guidance on Party Wall Notices?
We’re here to help you navigate the legal requirements and avoid costly mistakes.
Contact us at team@simplesurvey.co.uk
We’ll help you determine if a notice is required and guide you through the next steps.