Complete Guide to Party Wall Agreements in London 2026

Published January 2026 | Reading time: 12 minutes

If you're a London homeowner planning building work, understanding party wall agreements is essential. Party Wall Agreement London provides this complete guide to help you navigate the Party Wall etc. Act 1996, from serving your first notice to completing your project legally and maintaining good relations with your neighbours.

What Is a Party Wall Agreement?

A party wall agreement, properly called a party wall award, is a legal document prepared under the Party Wall etc. Act 1996. It sets out how building work affecting a shared wall or boundary will proceed and protects both the building owner undertaking works and the adjoining owner's property.

Many people mistakenly believe they need their neighbour's consent before starting work. In fact, the party wall agreement process exists specifically to allow building work to proceed even when neighbours object – but it must follow the Act's procedures exactly.

Understanding Party Walls

A party wall is a shared wall between two properties. In London's densely populated areas, millions of properties share party walls with their neighbours. These include:

• Walls between terraced houses that separate one property from the next
• Walls between semi-detached properties
• Walls separating flats in the same building
• Garden walls on the boundary line (party fence walls)
• Walls built partly on each property (astride the boundary)

The party wall structure is shared by both property owners. While you each own the part on your side, neither owner can make changes without following the Party Wall Act procedures.

When Do You Need a Party Wall Agreement London?

The Party Wall Agreement London process applies to three main types of work:

1. New Boundary Walls (Section 1)

Building a new wall at or astride the boundary between properties requires notice under Section 1 of the Act. You can build right up to the boundary line without your neighbour's consent, but building astride (across) the boundary requires express consent.

Common Section 1 works include:

• Flank walls of side extensions built at the boundary
• New garden walls along the property line
• Walls for detached outbuildings at the boundary

2. Work to Existing Party Structures (Section 2)

Section 2 covers alterations to existing party walls and party fence walls. This is the most common type of party wall work in London and includes:

• Raising a party wall: Common in loft conversions when you need to build the party wall higher to accommodate your new roof structure
• Cutting into a party wall: When inserting steel beams for extensions or loft conversions
• Removing chimney breasts: Especially when the chimney is attached to or passes through the party wall
• Underpinning a party wall: Essential for basement extensions
• Rebuilding party fence walls: When your garden wall is damaged or too low for your extension
• Exposing a party wall: When demolishing part of your building or your neighbour's building is demolished

Section 2 works require 2 months notice before work starts. This longer period gives adjoining owners time to appoint a surveyor and prepare a schedule of condition.

3. Excavation Near Boundaries (Section 6)

Section 6 applies when excavating within certain distances of your neighbour's building. This is crucial for basement extensions and foundation work:

• 3-metre rule: If you excavate within 3 metres of your neighbour's building and go deeper than their foundations
• 6-metre rule: If you excavate within 6 metres and a 45-degree line drawn downwards from the bottom of their foundation would intersect your excavation

Most Victorian and Edwardian properties in London have shallow foundations (600mm-1000mm deep). Modern building regulations require minimum 1-metre depths, so many basement conversions and even some extensions trigger Section 6.

The Party Wall Agreement Process: Step by Step

Step 1: Determine if the Act Applies

Review your architectural plans with a party wall surveyor to identify which types of work fall under the Act. Many homeowners are surprised to learn that seemingly minor works like installing bathroom fixtures that require cutting into a party wall need party wall procedures.

Step 2: Serve Party Wall Notices

The building owner (you, if undertaking the work) must serve written notice on all adjoining owners. The notice must include:

• Your name and address
• The address of the property where work will occur
• Detailed description of proposed works
• Date when work will start (at least 1-2 months away)
• Statement that it's a notice under the Party Wall Act 1996

Notice must be properly served – ideally by recorded delivery or hand delivery with proof. Email or standard post isn't sufficient unless the adjoining owner agrees.

Step 3: Await Response (14-Day Period)

After receiving your party wall notice, the adjoining owner has 14 days to respond in one of three ways:

1. Consent: They agree in writing, and work can proceed after the notice period. No surveyors needed, though many homeowners still request a schedule of condition.
2. Dissent and appoint their own surveyor: The adjoining owner wants their own party wall surveyor to protect their interests.
3. Dissent and agree to an agreed surveyor: Both parties use one surveyor who acts impartially for both building owner and adjoining owner.

If the neighbour doesn't respond within 14 days, they're deemed to have dissented. You must then appoint a surveyor on their behalf to ensure the process continues lawfully.

Step 4: Appoint Party Wall Surveyors

When there's a dispute (dissent), surveyors must be appointed. There are two models:

Two surveyors: You appoint your building owner's surveyor, your neighbour appoints their adjoining owner's surveyor. The two surveyors work together and select a third surveyor at the outset (in case they can't agree on any aspect).

Agreed surveyor: One surveyor acts impartially for both parties. This is often more cost-effective for straightforward projects like single-storey extensions.

Step 5: Schedule of Condition

Before work starts, the adjoining owner's surveyor (or agreed surveyor) prepares a schedule of condition. This photographic survey documents the current state of the adjoining property, recording any existing cracks, damage, or defects.

A thorough schedule of condition includes:

• Exterior photos of walls, roofs, and structures
• Interior photos of rooms adjacent to the party wall
• Detailed descriptions of existing damage
• Measurements of significant cracks
• Date-stamped images for evidence

This document protects everyone: the building owner from false damage claims, and the adjoining owner by providing clear evidence if damage does occur.

Step 6: Prepare the Party Wall Award

The appointed surveyor(s) prepare a party wall award that legally authorizes the work. The award specifies:

• Scope of works: Exactly what work is permitted
• Time and manner: When work can occur, working hours, noise restrictions
• Access rights: If and when builders can access the adjoining property
• Protective measures: What the building owner must do to prevent damage
• Costs: Who pays for what, including surveyor fees
• Schedule of condition: Attached to the award as evidence

For example, an award might require that cutting into the party wall for steel beams be done by hand tools only (not power saws), or that excavation proceed in 1-metre sections with temporary supports.

Step 7: Serve the Award

Once finalized, the party wall award is "served" on both building owner and adjoining owner. This is a legal document, and work can only lawfully commence once:

1. The award has been served
2. The statutory notice period has passed (or been waived)
3. The award hasn't been appealed (14-day appeal period)

Step 8: Undertake Building Work

Your contractors can now start work, following the conditions in the party wall award. The surveyors may make site visits during construction to check compliance and monitor for any damage.

Step 9: Final Inspection

After work completes, the adjoining owner's surveyor conducts a final inspection, comparing the property's condition against the original schedule of condition. If damage has occurred:

• The building owner's contractor can make repairs
• Or the adjoining owner can receive compensation to arrange their own repairs
• Disputes about damage or repair costs go to the appointed surveyors for resolution

Common Party Wall Scenarios in London

Loft Conversions

Most loft conversions need party wall procedures. When converting your loft, you'll typically need to raise the party wall to accommodate the new roof structure and install steel beams through the party wall to support your new floor.

The party wall surveyor will ensure your structural engineer's design doesn't overload the party wall, that beam insertions are done safely, and that your neighbour's roof structure isn't compromised.

Rear Extensions

Single-storey and two-storey rear extensions often involve building a new wall at the boundary (Section 1) and may require cutting into the party wall for structural openings (Section 2). If excavating for foundations, Section 6 may also apply.

The party wall award will address how close you can build to the boundary, protective measures during excavation, and how roof flashings will be installed against the party wall without causing water damage.

Basement Extensions

Basement conversions are the most complex party wall matters. They typically involve:

• Section 6 excavation notices (almost always)
• Section 2 work to underpin the party wall
• Extensive schedules of condition
• Structural monitoring during works

Party Wall Agreement London strongly recommends using two surveyors for basement projects due to their complexity and the higher risk of affecting adjoining properties.

How Much Does a Party Wall Agreement Cost?

Party wall surveyor fees in London vary by project complexity:

• Simple rear extension: £500-£1,200 per surveyor
• Loft conversion: £800-£1,500 per surveyor
• Basement extension: £2,000-£5,000+ per surveyor
• Agreed surveyor (both parties): Often 20-30% more efficient than two surveyors but split between parties

Remember, the building owner typically pays for both their own surveyor and the adjoining owner's surveyor. This is because you're benefiting from the building work.

Top 10 Party Wall Agreement Mistakes to Avoid

1. Starting work before serving notice: This is unlawful and your neighbour can get an injunction stopping your work
2. Assuming consent means no procedures needed: Even with consent, get a schedule of condition to protect yourself
3. Serving notice too late: Remember the 2-month period for Section 2 works – plan ahead
4. Not identifying all adjoining owners: You must serve notice on all affected parties, including tenants in some cases
5. Ignoring Section 6 requirements: Many builders forget about excavation rules for foundations
6. Choosing the cheapest surveyor: Quality matters – poor surveyors can delay your project or create disputes
7. Not reading the award properly: Ensure your contractor understands and follows award conditions
8. Skipping the schedule of condition: You'll regret this if damage claims arise later
9. Poor communication with neighbours: The Act provides a framework, but good relations help tremendously
10. Assuming the Act doesn't apply to small works: Even minor works like installing a bathroom can need procedures if cutting into party walls

Do I Need a Party Wall Surveyor or Can I DIY?

Legally, you can serve party wall notices yourself without a surveyor. However, Party Wall Agreement London strongly recommends professional help because:

• Notices must include specific information – errors can invalidate them
• Identifying which sections of the Act apply requires expertise
• You might miss adjoining owners who need notice
• If disputes arise, you'll need a surveyor anyway
• Professional surveyors prevent costly delays and legal issues

For complex works like basement extensions, professional party wall surveyors are essential. For straightforward projects, at minimum get initial advice to ensure you're serving notice correctly.

What If My Neighbour Is Being Difficult?

The beauty of the Party Wall Act is that you don't need your neighbour's consent to proceed with building work. If they:

• Refuse to consent to your notice
• Don't respond within 14 days
• Are being obstructive

The dispute resolution process kicks in. Surveyors are appointed, and the party wall award legally authorizes your work to proceed. Your neighbour can't stop lawful building work by simply refusing to engage.

That said, maintaining good relations makes the process much smoother. Consider:

• Discussing plans informally before serving formal notice
• Explaining how you'll minimize disruption
• Offering to use an agreed surveyor to keep costs down
• Being flexible about working hours where possible
• Keeping them informed throughout the project

Party Wall Agreement London: Timeline Examples

Example 1: Simple Loft Conversion

• Week 1: Serve party wall notice (Section 2) to both neighbours
• Week 3: Both neighbours consent in writing
• Week 4: Agreed surveyor prepares schedule of condition
• Week 8: Statutory 2-month notice period ends
• Week 9: Building work starts
• Week 18: Work completes, final inspection shows no damage

Example 2: Disputed Basement Extension

• Week 1: Serve party wall notices (Sections 2 and 6) to all adjoining owners
• Week 3: One neighbour dissents, appoints their surveyor
• Week 4: Two surveyors appointed, third surveyor selected
• Week 5-6: Extensive schedule of condition prepared
• Week 7-8: Surveyors prepare detailed party wall award
• Week 9: Award served on both parties
• Week 11: 2-month notice period ends, work starts
• Week 35: Building work completes
• Week 36: Final inspection, minor cracks found
• Week 38: Repairs completed, project finalized

Recent Changes and 2026 Updates

While the Party Wall Act 1996 remains unchanged in its core provisions, recent case law and practice developments have clarified several areas:

• Digital notices: Courts now generally accept email service of notices if the adjoining owner consents, though recorded delivery remains safer
• Surveyor qualifications: RICS strongly recommends only appointing chartered surveyors with specific party wall experience
• Dispute resolution timeframes: Increased focus on expediting awards to prevent construction delays
• Climate considerations: Awards increasingly address sustainable construction methods and heat pump installations

Conclusion: Making Party Wall Agreements Work for You

Party wall agreements don't have to be complicated or confrontational. With proper planning, professional surveyors, and good communication, most party wall matters proceed smoothly.

Key takeaways:

• Start the party wall process early – at least 2-3 months before you need to start building
• Use experienced party wall surveyors who know London properties
• Always get a schedule of condition, even if your neighbour consents
• Communicate openly with neighbours throughout
• Follow the party wall award conditions strictly
• Budget for party wall costs in your overall project

Party Wall Agreement London has guided thousands of London homeowners through the party wall process. Whether you're planning a loft conversion, basement extension, or any building work affecting shared structures, our experienced surveyors ensure legal compliance and protect all parties' interests.

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