What is a Party Wall?

If you own, occupy, or plan to develop property in England or Wales, you will almost certainly encounter the question: what is a party wall? The term appears simple, yet it causes more confusion, neighbour disputes, and project delays than almost any other aspect of residential construction. You need a clear, practical understanding of what a party wall is, when it matters, and how it affects your legal rights and responsibilities.

A party wall is a shared structure that sits on or near the boundary between two properties and forms part of the legal framework governed by the Party Wall etc. Act 1996. The Act does not regulate ownership of land. It regulates how you carry out specific types of construction work that could affect a neighbouring property.

This guide explains what a party wall is, how the law defines it, how it differs from related structures, when the Act applies, and what you must do before starting work. It also explains common misunderstandings that regularly cause disputes.

Understanding the Party Wall: Legal Definition

A party wall is a shared wall or structure that separates and is jointly owned by the owners of adjoining properties. According to the Party Wall etc. Act 1996 (the Act), a “party wall” can take several forms:

1. A wall that forms part of a building and stands on land of different owners (more than just the foundation projecting over).

2. A wall that does not form part of a building but separates buildings belonging to different owners (a boundary wall used in common).

3. A party fence wall, which is a wall standing on the land of different owners but not forming part of any building, and used to separate adjoining lands.

Related : Party Wall Agreement

Key Types of Party Walls

To determine if a wall is a party wall, you must understand the type of structure and its positioning. The Act recognises three main types:

Party Walls forming part of a building: These are walls built astride the boundary line and form part of one or more buildings. A classic example is a terraced house wall shared with a neighbour.

Party Fence Walls: These are freestanding boundary walls built astride the boundary line but not forming part of any building.

Party Structures: These include shared floors and ceilings between flats or maisonettes in a multi-occupancy building.

Party wall meaning in everyday property situations

You encounter party walls most commonly in the following situations.

Terraced housing. The wall between adjoining houses is almost always a party wall. Both owners rely on it structurally and neither can treat it as their own exclusive structure.

Semi detached housing. The dividing wall between the two halves of the building usually qualifies as a party wall.

Converted buildings. In some conversions, walls between flats can qualify as party structures, especially where they separate parts of a building approached by separate staircases.

Urban infill and extensions. New walls built up to or astride a boundary can become party walls depending on their position and use.

Understanding whether a wall is a party wall depends on its legal position and function, not on who paid for it or who maintains it.

What is not a party wall?

Many disputes arise because owners assume a structure is a party wall when it is not. The Act draws clear distinctions.

A party wall is not the same as a boundary fence or fence panel. Timber fencing does not fall under the Act.

A party wall is not always a garden wall. Some garden walls qualify as party fence walls, but many do not.

A wall entirely on your land that does not support or separate a neighbouring building is not a party wall, even if it sits close to the boundary.

The Act focuses on shared structural or separating functions. Decorative or purely boundary features usually fall outside its scope.

What is a party fence wall?

The Act also defines a party fence wall, which often causes confusion.

A party fence wall is a wall, not forming part of a building, that stands astride the boundary and separates adjoining land. It usually appears in gardens rather than as part of a house.

Examples include brick or masonry garden walls that sit on the boundary line and serve both properties. The Act does not treat timber fences or concrete post and panel fencing as party fence walls.

If you propose to demolish, rebuild, raise, or otherwise alter a party fence wall, the Party Wall Act may apply in exactly the same way as it does to a party wall forming part of a building.

What is a party structure?

The Act uses the broader term party structure to capture walls and other elements that separate buildings or parts of buildings.

A party structure includes a party wall and can also include floors or partitions separating flats or commercial units where those parts are accessed independently.

This matters in buildings converted into flats, mixed use properties, and older structures with complex layouts. Work to floors and partitions can trigger the same notice and dispute procedures as work to walls.

Why the definition of a party wall matters

Understanding what is a party wall matters because the legal consequences are significant.

If your proposed work affects a party wall, party fence, or party structure, the Act grants you specific rights to carry out that work. At the same time, it imposes strict procedural duties designed to protect your neighbour.

If you ignore those duties, you expose yourself to injunctions, project delays, and legal costs. In serious cases, courts can order you to stop work immediately.

Why Party Walls Matter in Construction

Party walls are legally significant because of the rights and responsibilities they confer on adjoining owners. If one neighbour (known as the building owner) wants to carry out works affecting a shared structure, they must comply with specific notice procedures and obtain necessary consents from the other owner (the adjoining owner).

Typical examples of works that may affect a party wall include:

Building a new wall on the line of junction.

Cutting into a shared wall to insert steel beams or flashing.

Raising or thickening the wall.

Demolishing and rebuilding the wall due to structural defects.

Excavating near the foundation of a party wall or neighbouring structure.

The Party Wall etc. Act 1996: Overview

The Act provides a statutory framework for preventing and resolving disputes relating to party walls, boundary walls, and excavations near neighbouring buildings. It applies across England and Wales and came into force on 1 July 1997.

The key objectives of the Act are to:

Define what constitutes a party wall.

Establish procedures for giving notice of works.

Set out dispute resolution processes through surveyors.

Protect the rights of adjoining owners.

Ensure that damage is avoided or appropriately compensated.

The Act requires you to serve a Notice before starting works and allows the adjoining owner to either consent or dissent — with dissent triggering a formal dispute resolution process involving surveyors.

When Must You Serve a Party Wall Notice?

A building owner must serve a formal Notice under three scenarios:

1. Works on an existing party wall – including repairs, raising the height, cutting into it, or demolishing and rebuilding it.

2. Construction on the line of junction – when building a new wall astride or up to the boundary.

3. Excavation within 3 or 6 metres of a neighbouring structure and below the depth of its foundations.

Notice periods vary depending on the work:

Two months' notice for works to a party structure.

One month's notice for new walls on the boundary or excavation.

If the adjoining owner consents in writing, the works can proceed. If they dissent, the parties must appoint surveyors to resolve the matter and issue a legally binding Award.

What is a Party Wall Award?

An Award is a document prepared by one or more surveyors that determines:

What works are allowed.

How they will be carried out.

What protections must be in place for the adjoining owner.

Who pays for the work and surveyor costs.

The award ensures fairness and clarity and is enforceable in court. Either party can appeal the award within 14 days in the county court if they believe it was made improperly.

Rights and Responsibilities of Owners

Building Owners’ Rights:

Carry out specified work to the party wall, shared structures, or foundations.

Access the neighbour’s land with notice to carry out works.

Building Owners’ Duties:

Serve correct notice.

Avoid unnecessary inconvenience.

Compensate for any damage.

Comply with any PW agreement or award.

Adjoining Owners’ Rights:

Consent or dissent to proposed works.

Appoint their own surveyor.

Require security for expenses.

Claim compensation for damage.

Common Misunderstandings

“It’s my wall - I can do what I want.” Incorrect. If it is a party wall as defined under the Act, you cannot lawfully carry out works without notice - even if you built it originally.

“Party walls only apply to terraced houses.” False. Work to a flat, semi-detached house, and even commercial buildings can require Notice under the Act.

“There’s no need for a surveyor if we agree.” Not entirely accurate. While agreement avoids a dispute, a formal record like a Schedule of Condition is strongly advisable to prevent arguments over damage later.

What Happens if You Ignore the Act?

Failure to comply with the provisions of the Act can result in:

Injunctions stopping the work.

Court action and liability for damages.

Delays to the project.

Increased costs, including legal fees and remedial works.

The Role of Surveyors

When a dispute arises, both parties typically appoint surveyors under section 10 of the Act. These surveyors are not advocates but must act impartially. If the two surveyors cannot agree, they appoint a third surveyor who makes the final decision.

Surveyors ensure that:

The works are properly assessed and documented.

Damage is prevented or rectified.

The rights of both parties are respected.

They also determine costs and responsibility for payment of the award.

Practical Examples

Loft conversion: Inserting steel beams into a shared wall to support a new floor or roof structure.

Basement excavation: Digging below neighbouring foundations within three or six metres.

Rear extension: Building astride the boundary or cutting into the existing wall.

All these require appropriate notices and potential agreements or awards.

Conclusion

A party wall is not just a physical structure - it represents a legal relationship between neighbours that must be handled with care and precision. Under the Act, property owners have a statutory duty to notify, consult, and, if necessary, resolve disputes through an agreed framework.

Understanding what is a party wall is, and knowing when and how the Act applies, can help homeowners, developers, architects, and surveyors avoid unnecessary conflict, delay, and legal costs.

If you are planning work near a shared wall or boundary, it is wise to consult a qualified surveyor experienced in neighbourly matters early in the process to ensure compliance and maintain good neighbourly relations.

Get in Touch

Need further help or advice?

For advice direct from one of our Surveyors, please call our Enquiry line on 020 4534 3135.

If you would rather we called you instead, please fill in our Contact form and we will be in touch.

For a quick online quote, send us the details of your project. For more articles on all aspects of this service see our blog.

For advice direct from one of our Surveyors, please call our Enquiry line on 020 4534 3135.

If you are planning work that is covered by the Act, or if you have received notice of work from a neighbour and want advice on how best to protect your property please contact: