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If you’ve searched online for a “third party wall agreement”, you’re not alone. It’s a very common phrase used by homeowners planning an extension, loft conversion, or basement project, particularly in London.
However, here’s the truth straight away: there is no legal document called a “Third Party Wall Agreement” in the Party Wall etc. Act 1996.
So why does the term exist?
In most cases, people are actually looking for one of two things:
This guide clears up the confusion, explains the correct legal terminology, and shows you how to properly protect your property rights without getting caught out by misleading phrases.
Legally speaking, no, a “third party wall agreement” does not exist.
What homeowners commonly call a party wall agreement is formally known as a Party Wall Award. This is the document produced under the Party Wall etc. Act 1996 that governs how building work affecting a shared wall or boundary must be carried out.
The Act itself never uses the phrase third party wall agreement.
The confusion usually arises because:
Over time, this has led to the incorrect but widely searched term third party wall agreement.
Understanding this distinction is important, especially if a disagreement arises and legal clarity matters.
When homeowners talk about a Is There Such a Thing as a “Third Party Wall Agreement”?, they are usually referring to the Third Surveyor, a very specific statutory role under the Act.
Under Section 10 of the Party Wall etc. Act 1996, if:
Then those two surveyors must immediately select a Third Surveyor.
This appointment happens at the start of the process not when a dispute arises.
Most homeowners will never meet or speak to the Third Surveyor.
Why?
Think of the Third Surveyor as an insurance policy, present just in case.
If a deadlock occurs between the two surveyors (for example, over construction methods, access, or damage responsibility), the matter can be formally referred to the Third Surveyor.
At that point, the Third Surveyor:
In effect, they act like a judge but without the need for court proceedings.
Even though the phrase is incorrect, homeowners asking how to get a third party wall agreement are really asking how the Party Wall Award process works.
Here’s how it happens step by step.
The Building Owner must serve a formal Party Wall Notice on all relevant Adjoining Owners.
This includes:
The notice outlines the proposed works and starts the legal process.
If the neighbour:
A dispute is deemed to have arisen under the Act.
This does not mean the neighbour is objecting to the works, it simply triggers the professional surveyor process.
At this point, one of two things happens:
The appointed surveyor(s) prepare the Party Wall Award, which:
This is the document most people mean when they say “third party wall agreement.”
In the vast majority of residential projects, the Building Owner pays.
This reflects the principle of the Act:
The person benefiting from the works should bear the reasonable costs.
A key point often misunderstood:
If the Third Surveyor is called upon:
Typically:
It’s easy to get caught up in phrases like third party wall agreement, but the terminology is far less important than the legal protection.
What matters is that:
Done correctly, the process protects both properties, prevents disputes, and keeps your project moving.
Confused about party wall terminology or your legal position?
No. In the UK, the legal document is called a Party Wall Award. The phrase third party wall agreement is a common search term used by homeowners looking for professional involvement in creating a legally binding agreement.
When each owner appoints their own surveyor, those two surveyors must select a Third Surveyor. This person acts as an independent referee and only becomes involved if there is a disagreement between the first two surveyors.
Usually, no. In most residential projects, the Third Surveyor is never contacted directly by the owners. You may only see their name listed in the Party Wall Award unless a formal referral is made.
The Third Surveyor decides this themselves. In most cases, the Building Owner pays but if the referral was unnecessary, the Third Surveyor can order the other party to cover the cost.
If both neighbours consent in writing, no surveyor or Award is required. However, for most London projects (lofts, extensions, basements), a professional Schedule of Condition is strongly recommended to prevent future damage disputes.
