What to Do if Your Neighbour is Building Without a Party Wall Agreement
Not every extension needs party wall notices, but many do, especially if it is built on the boundary, attaches to a shared wall or involves deep foundations close to your home. Ask politely, record the position and take advice.
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- Take dated photos of the boundary, shared walls and your side of the property.
- Photograph existing cracks and finishes inside affected rooms.
- Ask your neighbour in writing whether party wall notices have been served.
- Ask to see the plans and how deep the foundations will be.
- Check the council planning portal for the approved drawings.
- Speak to a party wall surveyor if the works touch or come close to your property.
What to say to your neighbour
Keep it short and friendly. For example: "Hi, I noticed work starting on the extension. Could you let me know whether party wall notices have been served, and share the drawings? I would like to have my own surveyor look at it so we both stay protected."
Put the same message in writing (email or letter) so you have a record.
When an extension needs notices
A ground floor extension may fall under the Act if it involves building on the line of junction, cutting into or attaching to an existing party wall, or excavating within 3 or 6 metres of your building in the circumstances the Act describes.
An extension set well away from the boundary and your foundations may not need any notice. Your neighbour or their builder should know which applies.
Planning is separate
Planning permission and building regulations approval do not replace party wall notices. A neighbour who has planning consent may still need to serve notices. Equally, no objection to planning does not mean you agreed to anything under the Act.
If no notice has been served
The Act has no criminal penalty for missing a notice. The remedies are civil. You may ask the neighbour to serve notices, appoint a surveyor, or in serious cases apply to the court for an injunction.
Foundations are the critical stage. Once they are in and covered, it is harder to check what was done. Act early if excavation has begun.
Approach with care
A friendly conversation usually works better than a letter of complaint. Suggest they speak to a party wall surveyor. Do not enter their land or interfere with the builders.
Frequently asked questions
Do I have to agree to the extension?
You cannot block work that falls within the Act by refusing consent. You can dissent, which leads to a surveyor and an award that protects you.
Can I stop them digging foundations?
Not by yourself. Raise it in writing, involve a surveyor, and use the court only on advice.
Do I pay for my surveyor?
Normally the building owner pays reasonable fees where the work is for their benefit. The award decides.
Is the council responsible?
No. Councils do not enforce the Act.
Related guides
- What to Do If Your Neighbour Starts Building Work Without Telling You
- Party Wall Rules for Home Extensions
- Excavations and Foundational Underpinning: Party Wall Rules Explained
- What is the Retrospective Party Wall Procedure? (When Work Starts Without a Notice)
Last updated: . This page is general information about the Party Wall etc. Act 1996 (England and Wales). It is not legal advice. Every property and dispute is different, so take advice from a party wall surveyor or a solicitor before you act.