Hourican Associates Ltd | 01-09-2025

Planning building works in London? Certain projects that affect a shared wall, boundary, party structure or nearby foundations require a Party Wall Notice and either written neighbour consent or, where consent is not given, a Party Wall Award in London. Homeowners often call this a Party Wall Agreement. This guide explains when you legally need one, how the process works, and why using a chartered party wall surveyor in London helps avoid costly delays and disputes.

What Is a Party Wall Agreement?

“Party Wall Agreement” is the everyday phrase many London homeowners use when talking about the Party Wall process. Strictly speaking, the Party Wall etc. Act 1996 refers to notices, written consent, disputes and Party Wall Awards.

Depending on how your neighbour responds, a Party Wall Agreement may mean:

• written consent from the adjoining owner after a valid Party Wall Notice has been served; or
• a formal Party Wall Award prepared by one Agreed Surveyor or by two appointed surveyors if there is dissent, no response or a dispute.

A formal Award typically sets out:

• The exact works permitted and methods of construction.
• Working hours and access arrangements.
• A Schedule of Condition of the adjoining owner’s property before works begin.
• Procedures for resolving disputes, dealing with access and making good any damage.

When Do You Need to Serve a Party Wall Notice?

Before starting notifiable works, the building owner must usually serve the correct notice on every relevant adjoining owner. The notice type depends on the work being carried out.

1) Works to a Party Wall or Party Structure — Section 2 Notice

• Cutting into a party wall, such as inserting steel beams for a loft conversion.
• Removing or enclosing a chimney breast attached to a shared wall.
• Raising, thickening, underpinning or demolishing a party wall.
• Inserting flashing, damp-proof courses, padstones or structural supports.

For party structure works, the notice period is usually two months. If the adjoining owner dissents or does not respond, you will normally need a Party Wall Award service before the notifiable works start.

2) Excavation Near Neighbouring Foundations — Section 6 Notice

• Excavating within 3 metres of a neighbouring structure to a lower level than its foundations.
• Excavating within 6 metres where the 45° line criteria applies.

Common examples: rear extensions, side returns, new foundations, underpinning, lower-ground extensions and basement construction. For Section 6 excavation notices, the notice period is usually one month.

3) New Walls on or at the Boundary — Section 1 Notice

• Building a new wall on the line of junction, also known as the boundary.
• Building a new wall astride the boundary, which requires the neighbour’s written consent.
• Constructing a new party fence wall, such as a masonry garden wall built on the boundary.

For Section 1 line of junction notices, the notice period is usually one month.

Do You Always Need a Full Party Wall Agreement?

No. If you serve a valid notice and your neighbour consents in writing within the required response period, a full Party Wall Award may not be required. However, a Schedule of Condition Survey is still strongly recommended before works start.

If the adjoining owner dissents, raises concerns, or does not reply where the Act treats this as a dispute, surveyor appointments are normally required. The appointed surveyor or surveyors then prepare a formal Party Wall Award that regulates how the works may proceed.

Why Use a Chartered Party Wall Surveyor?

• Correct, legally valid notices under the Act.
• Clear advice on whether consent, an Agreed Surveyor or a full Party Wall Award London service is required.
• Independent, impartial administration of the process.
• Robust Schedule of Condition to protect all parties.
• Clear procedures for access, working methods, safeguards and damage resolution.

Hourican Associates are regulated by RICS, and members of the FPWS, CIOB, and MCABE.

Typical London Projects That Trigger the Act

• Loft conversions involving steel beams.
• Rear and side extensions.
• Basement excavations and underpinning.
• Chimney breast removals.
• New boundary or party fence walls.
• Excavations within 3 metres or 6 metres of neighbouring structures.

What Happens if Your Neighbour Dissents?

A neighbour’s dissent does not necessarily mean your project cannot proceed. It means the statutory dispute resolution process has started. The owners can either appoint one impartial Agreed Surveyor, or each owner can appoint their own surveyor.

The surveyor or surveyors will then prepare a Party Wall Award surveyor in London document, setting out how the notifiable works are to be carried out, how the adjoining property is protected, what access is permitted, and how any damage should be dealt with.