Party Wall Notices: What They Are and How to Serve One

What is a Party Wall Notice?

A party wall notice is a formal written document that you must give to your neighbour before starting building work that falls under the Party Wall etc. Act 1996. It tells your neighbour what work you intend to carry out, when you plan to start, and gives them an opportunity to consent or raise concerns.

Serving a notice is a legal requirement, not a courtesy. Starting work without serving a valid notice can expose you to injunctions, legal claims, and disputes that are far more costly and time-consuming than the notice process itself.

When Do You Need to Serve a Notice?

You must serve a party wall notice if you plan to:

Do any work directly to a shared (party) wall — for example, cutting in steels for a loft conversion or extension
Build a new wall at or along the boundary between your property and a neighbour's
Excavate within 3 or 6 metres of a neighbouring building where your digging will go below the level of their foundations

If you are not sure whether your planned work requires a notice, our free quiz can help you find out in a few minutes.

The Three Types of Notice

1. Party Structure Notice (Section 3)

This is the most common type of notice. It is required when you intend to carry out work directly to an existing party wall or party structure.

Examples include cutting into the party wall, inserting steel beams, raising the wall height, removing a chimney breast, or underpinning.

You must serve this notice at least two months before work is due to begin.

2. Line of Junction Notice (Section 1)

This notice is required when you plan to build a new wall at or astride the boundary line between your property and your neighbour's.

You must serve this notice at least one month before work is due to begin.

3. Adjacent Excavation Notice (Section 6)

This notice is required when your planned excavation will take place within a certain distance of a neighbouring building and will go below the level of their foundations:

Within 3 metres, where your excavation goes deeper than the neighbour's foundations
Within 6 metres, where your excavation would undercut a line drawn downwards at 45 degrees from the base of their foundations

This typically applies to deep foundation trenches, basement work, or significant groundworks near a shared boundary.

You must serve this notice at least one month before work is due to begin.

What Must a Notice Include?

To be legally valid, a party wall notice must include:

Your full name and address (and that of any joint owners)
The address of the property where the work will take place
A clear description of the proposed works
The planned start date
For excavation notices: plans and sections showing the depth of excavation and proximity to the neighbouring structure

Vague or incomplete notices can be deemed invalid, which would require you to restart the process and could delay your project significantly.

How to Serve a Notice

A party wall notice must be served in writing — it cannot be given verbally.

You can serve it by:

Hand delivery — directly to the adjoining owner or through their letterbox
Post — sent to the owner's last known address (recorded delivery is advisable to prove receipt)
Email — only if the adjoining owner has given their prior written consent to receive documents electronically

Always keep a copy of the notice and a record of how and when it was served. A signed acknowledgement or delivery receipt is useful evidence if the process is later disputed.

If there are multiple adjoining owners — for example, both a freeholder and a leaseholder at a neighbouring property — you must serve notice on each of them individually.

What Happens After You Serve the Notice?

Your neighbour has 14 days from the date the notice is received to respond. They can:

Consent in writing — the works can proceed once the relevant notice period (one or two months) has elapsed
Dissent — this triggers the dispute resolution process and requires the appointment of a party wall surveyor
Do nothing — silence is treated in law as dissent, with the same result

If your neighbour consents, no surveyor is needed and you can proceed with your works. Our Party Wall generates all the documents required for this outcome: the notice itself and the neighbour's consent letter.

What is Deemed Dissent?

If your neighbour does not respond within 14 days, the law automatically treats this as dissent — even if they have no objection. This is known as deemed dissent, and it means a dispute is considered to have arisen under the Act, triggering the need for surveyors and a formal Party Wall Award.

This is one reason why informal communication with your neighbour before serving notice is a good idea. If they know what to expect and are broadly supportive, they are more likely to respond promptly and in writing. Our guide on discussing your plans with your neighbour walks through how to approach this conversation.

How Long is a Notice Valid?

A party wall notice is valid for 12 months from the date it is served. If work has not started within that period, a new notice must be served before beginning.

Common Mistakes to Avoid

Not serving all owners — if a property has more than one owner, serve notice on each individually
Vague descriptions — be specific about what work will be done and when
No proof of service — always keep evidence that the notice was received
Serving too late — the notice period (one or two months) must elapse before work starts, so factor this into your project timeline
Starting without a response — waiting for the 14-day response window to close before assuming consent is not valid; only written consent allows you to proceed without a surveyor