Party Wall Agreements London: Complete Guide for Homeowners

The Party Wall etc. Act 1996 governs works that affect shared walls, boundary walls, and excavations near neighbouring buildings. It applies to properties in England and Wales.

**The Act covers three main categories of work**:

**Section 1 — New building on or at the boundary line**: If you are building a new wall on the boundary, or within 3 metres of the boundary, you must serve a Line of Junction notice on your neighbour.

**Section 2 — Works to an existing party wall or party structure**: A 'party wall' is a wall shared between two properties (such as the wall between two terraced houses). A 'party structure' includes the floor between a ground floor flat and an upper flat in the same building.

• Works triggering a Section 2 notice include:
• •Cutting into a party wall to install a steel beam (RSJ) — very common in extensions
• •Underpinning a party wall (basement conversions)
• •Demolishing and rebuilding a party wall
• •Building up or reducing the height of a party wall
• •Inserting a damp proof course across a party wall
• •Removing a chimney breast that is in the party wall

**Section 6 — Excavation near a neighbouring building**: If you are excavating within 3 metres of a neighbouring building and the excavation goes below the level of the neighbouring foundation, you must serve a notice.

This applies to: rear extensions (if the new foundation is within 3 metres of the party wall or neighbour's building), basement conversions (almost always), swimming pools, deep drainage works.

**Note**: the Act does not give you permission to do the work — it is separate from planning permission and Building Regulations. It is a dispute resolution mechanism.

The party wall process has four possible paths, depending on whether your neighbour agrees or disputes the works:

• **Step 1: Serve the notice**
• You (the building owner) serve the relevant notice on the adjoining owner (your neighbour). The notice must:
• •Be in writing
• •Describe the works
• •State the intended start date (at least 2 months before starting for Section 2 works; 1 month for Section 6; 1 month for Section 1)
• •Include your name and contact details
• •Be served at the neighbour's address (or last known address)

There is no government-prescribed form but templates are available. Party wall surveyors can serve notices on your behalf.

• **Step 2: The neighbour responds (within 14 days)**
• The adjoining owner has 14 days to respond:
• •**They consent in writing**: the work can proceed. Record their consent carefully.
• •**They do not respond**: they are deemed to have dissented. A dispute is now deemed to exist and a Party Wall Award must be made.
• •**They dissent in writing**: a Party Wall Award must be made.

• **Step 3: Appointing surveyors**
• If a dispute exists (through non-response or dissent):
• •You appoint your own surveyor (Agreed Surveyor — who acts for both parties — or your own surveyor)
• •The adjoining owner appoints their own surveyor (if they don't, you appoint one on their behalf)
• •The two surveyors together (or the Agreed Surveyor) produce the Party Wall Award

• **Step 4: The Party Wall Award**
• The Award is a legal document that:
• •Records the condition of the neighbouring property before works begin (a Schedule of Condition)
• •Sets out the permitted works in detail
• •Specifies working hours, noise limits, and protective measures
• •Establishes the right to access the neighbouring property if necessary
• •Records any modifications to the works required to protect the neighbour

The Award takes approximately 4–8 weeks to agree between surveyors. More contentious situations (large basements, complex structural works, uncooperative neighbours) take longer.

**Step 5: Works proceed under the Award** Once the Award is in place, works can proceed. If the neighbour suffers damage during the works, they can claim compensation — the Schedule of Condition provides the baseline.

Given the density of London's terraced and semi-detached housing, the Party Wall Act applies to a very high proportion of home improvement projects. The most common triggers:

**Rear extensions**: Almost always trigger Section 2 (if the rear wall of the extension is built up to the party wall, or if the extension involves cutting into the party wall for RSJ bearings) and/or Section 6 (if the new foundation is within 3 metres of the neighbouring building and below their foundation level).

**Loft conversions**: Most loft conversions require cutting into the party wall to install the new structural floor/ceiling joist system, and to install steel beams where load-bearing walls are removed below. Section 2 notices required.

**Side return extensions**: Almost always trigger Section 1 (new wall at the boundary line) or Section 2 (if the party wall is affected).

**Basement conversions**: Always trigger Section 6 (excavation within 3 metres of neighbouring foundation below existing foundation level). Often also trigger Section 2 (underpinning of the party wall).

**Structural alterations (chimney breast removal, wall removal)**: Section 2 if the chimney breast or wall is in or immediately adjacent to the party wall.

**Internal works only**: If the works are entirely internal and do not affect the party wall, the Party Wall Act does not apply. However, 'affecting' the party wall includes cutting into it — even if only to insert a joist hanger.

**Party wall surveyor fees (London, 2026)**:

Under the Act, the building owner (who is doing the works) normally pays both surveyors' fees if a dispute arises. The surveyor fees are set by the surveyors — there is no fixed scale, but typical London rates:

• •Building owner's surveyor (your surveyor): £700–£1,500 per award
• •Adjoining owner's surveyor (neighbour's surveyor): £900–£2,000 per award

If there are multiple neighbours (typical in a terrace — two direct party walls), separate awards must be made with each. Total party wall costs for a standard London rear extension with 2 neighbours: £2,000–£5,000 typically.

For a basement project with 4 neighbours and complex structural conditions: £8,000–£20,000 in party wall costs is not unusual.

**Using an Agreed Surveyor**: if both you and your neighbour agree to use a single Agreed Surveyor (one person acting for both parties), costs are lower — typically £1,200–£2,500 for an Agreed Surveyor acting on a standard rear extension. The Agreed Surveyor must be independent and is not your personal surveyor.

• **Timescales**:
• •Notice period: 1–2 months depending on the section
• •Time to respond: 14 days
• •Time to agree Award (no dispute): 4–6 weeks
• •Time to agree Award (disputed): 6–16 weeks
• •Large basement with contentious neighbours: can take 4–6 months

**Planning ahead**: the party wall process must be factored into the project programme. A rear extension that could start in spring may not legally be able to start until autumn if the party wall process is not initiated early. rcbGroup advises all clients to initiate the party wall process as soon as architectural drawings are available — before planning is even submitted — to avoid delays.

**Do not start works before serving notices**: Starting works that require party wall notices without serving them first is a trespass and a breach of the Act. Neighbours can apply to the court for an injunction to stop the works. This is disruptive and expensive.

**Serve notices early**: The earlier you serve notices, the earlier the process begins and the earlier awards can be made. Serve notices at the design stage — before planning is submitted. Notices can be served and an award made before planning permission is granted.

**Record the condition of your neighbour's property**: Even if your neighbour consents to the works, commission a Schedule of Condition of the neighbouring property before works start. A professional surveyor photographs and records the condition of all rooms adjacent to the works. This protects you if the neighbour later claims damage that pre-existed the works.

**Good neighbour communication**: The best party wall situations start with a neighbourly conversation — explaining what you are doing, showing them the drawings, and answering their questions before the formal notice arrives. Many neighbours consent promptly once they understand the works and are reassured. Formal legal notices arriving out of the blue, without prior conversation, are more likely to result in formal disputes.

**Do not use your architect or builder as the party wall surveyor**: The party wall surveyor must be independent. Using your builder or architect creates a conflict of interest. They can however recommend qualified surveyors — look for members of the Faculty of Party Wall Surveyors or Pyramus & Thisbe Club.