What is a party wall agreement?

A party wall agreement (technically a 'party wall award') is a legally binding document that sets out the details of proposed building work that affects a shared wall, boundary, or nearby structure. It's required under the Party Wall etc. Act 1996 when you want to carry out certain types of building work near a neighbour's property. The agreement protects both you and your neighbour by recording the condition of the neighbouring property before work starts and setting out how the work should be done.

When do I need a party wall notice?

You need to serve a party wall notice if you plan to: build on or along the boundary line between your property and your neighbour's, cut into a party wall (shared wall), remove a chimney breast on a party wall, make a party wall taller/shorter/deeper, excavate within 3 metres of a neighbour's wall or structure (and deeper than their foundations), or excavate within 6 metres if the excavation would cut a 45-degree line from the bottom of their foundations. Common examples include loft conversions, extensions, basement excavations, and underpinning.

How much does a party wall surveyor cost?

If your neighbour dissents (doesn't consent), you'll typically need to appoint a party wall surveyor. Costs vary but typically: a single agreed surveyor costs £1,000–£2,000 for straightforward cases; if each party appoints their own surveyor, costs are £1,500–£3,500+ (and you, as the building owner, usually pay for BOTH surveyors). Complex cases involving basements or major structural work can cost £3,000–£10,000+. If your neighbour consents to the notice, you don't need a surveyor at all.

What happens if I don't serve a party wall notice?

If you carry out work that requires a party wall notice without serving one, you're in breach of the Party Wall Act. Your neighbour can seek an injunction to stop the work, and you could be liable for damages. You'd also have no protection if a dispute arises about damage to the neighbour's property. It's always better to comply — the process protects you as much as your neighbour. If you've already started work, you can still serve a notice retrospectively, though this isn't ideal.

Party Wall Agreement Guide — The Party Wall Act Explained

If you’re planning building work near a shared wall or boundary, you may need a party wall agreement. Here’s how the process works.

What Is a Party Wall?

Type	Description
Party wall	A wall shared between two properties (e.g. the wall between semi-detached or terraced houses)
Party fence wall	A wall on a boundary that isn’t part of a building (e.g. a garden wall on the boundary)
Party structure	A floor or other structure shared between properties (e.g. a flat floor/ceiling)
Boundary	The line separating your property from your neighbour’s

When You Need to Serve Notice

Work planned	Notice required?
Building on or along the boundary line	Yes — Party Structure Notice
Cutting into a party wall (e.g. inserting a beam)	Yes — Party Structure Notice
Making a party wall taller, shorter, or deeper	Yes — Party Structure Notice
Removing a chimney breast on a party wall	Yes — Party Structure Notice
Loft conversion involving the party wall	Yes — Party Structure Notice
Excavation within 3 metres of neighbour’s wall/structure and deeper than their foundations	Yes — Notice of Adjacent Excavation
Excavation within 6 metres cutting a 45° line from bottom of neighbour’s foundations	Yes — Notice of Adjacent Excavation
Building an extension near the boundary	Usually yes (depends on proximity)
Internal work that doesn’t affect party wall	No
Work more than 6 metres from any neighbour’s structure	No

The Party Wall Process

Step	Action	Timeframe
1	Decide what work you’re planning	Before serving notice
2	Serve a party wall notice on all affected neighbours	At least 2 months before work starts (1 month for excavation)
3	Neighbour responds: consent or dissent	Neighbour has 14 days to respond
4a	If consent: proceed with work (no surveyor needed)	Immediate
4b	If dissent or no response: appoint party wall surveyor(s)	Allow 4–8 weeks
5	Surveyor produces a party wall award	Sets out terms, schedule of condition, and payment responsibilities
6	Begin work in accordance with the award	Follow all conditions
7	After work: surveyor inspects for any damage	Within reasonable time

Serving Notice

Element	Detail
Form	Written notice (template letters available online or from your surveyor)
How to serve	Hand-deliver or send by post (keep proof)
What it must include	Your name and address, the address of the building, details of the proposed work, proposed start date
Timing	At least 2 months before work starts (Line of Junction or Party Structure Notice), 1 month for excavation notice
Expires	If work hasn’t started within 12 months, you must serve a new notice

Three Types of Notice

Notice type	When to use
Line of Junction Notice	Building a new wall on or along the boundary line
Party Structure Notice	Work affecting an existing party wall or party structure
Notice of Adjacent Excavation	Excavation within 3 or 6 metres of neighbour’s structure

What Your Neighbour Can Do

Response	What happens next
Consent (in writing)	Work can proceed — no surveyor needed
Dissent (in writing)	Surveyor process begins
No response within 14 days	Treated as a deemed dissent — surveyor process begins

Party Wall Surveyors

Option	Detail
Agreed surveyor	Both parties agree on one surveyor to act for both — cheaper and simpler
Two surveyors	Each party appoints their own surveyor — the two surveyors then produce the award
Third surveyor	If the two surveyors can’t agree, a third surveyor is appointed to resolve the dispute

Costs

Scenario	Typical cost
Neighbour consents	£0 (no surveyor needed)
Agreed surveyor (simple case)	£1,000–£2,000
Two surveyors (you pay both)	£1,500–£3,500
Complex case (basement, major structural)	£3,000–£10,000+

Important: As the building owner (the one doing the work), you usually pay all surveyor costs — both your surveyor and your neighbour’s.

The Party Wall Award

Element	What it covers
Details of the work	Exactly what work is permitted
Schedule of condition	Photographic and written record of the neighbour’s property before work starts
Method of working	How the work should be carried out
Working hours	When work can take place
Access	Whether access to the neighbour’s property is needed
Cost responsibility	Who pays for what (usually the building owner)
Damage	How any damage will be dealt with and who pays for repairs

Dispute Resolution

Issue	Resolution
Disagree with the award	Appeal to the County Court within 14 days
Damage caused during work	Surveyor inspects and determines responsibility (usually building owner pays)
Neighbour refuses access for schedule of condition	Surveyor records what they can from outside
Work doesn’t comply with the award	Neighbour can seek injunction or claim for damages

Common Scenarios

Project	Likely notices needed
Rear extension	Party Structure Notice (if near party wall) + possible excavation notice
Loft conversion	Party Structure Notice (cutting into or raising party wall)
Basement conversion	Excavation notice + Party Structure Notice
Removing chimney breast	Party Structure Notice
New garden wall on boundary	Line of Junction Notice
Underpinning	Excavation notice
Kitchen extension (side return)	Party Structure Notice + possible excavation notice

Tips for a Smooth Process

Tip	Detail
Talk to your neighbour first	Explain your plans informally before serving legal notices
Serve notice early	Don’t leave it until the last minute — aim for 3+ months before work starts
Use an experienced party wall surveyor	They handle the process and reduce conflict
Pay for good schedule of condition photos	Protects you if damage is disputed
Keep copies of everything	Notices, responses, the award, photos
Be a good neighbour	Minimise disruption, stick to agreed hours, communicate

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