Fact 48. Party Wall Act - when do you need an agreement and what does it involve?
The Party Wall Act 1996 requires formal agreement before building work affecting shared walls, boundaries, or excavations near neighbouring properties to prevent disputes.
The Party Wall Act 1996 is an essential but often misunderstood piece of legislation governing how building work near shared boundaries must be handled.
Many homeowners only discover its importance when preparing to start a project, only to realise that formal notices and agreements are legally required before work can begin. Understanding when you need a Party Wall Agreement, why it matters, and what the full process involves can prevent legal disputes, delays, and unexpected costs.
In England and Wales, the Act provides a clear framework for preventing and resolving disputes between neighbouring owners when works affect shared or adjoining structures. Whether you’re cutting into a wall for a loft conversion, excavating for a new extension, or building a wall precisely on the boundary line, compliance with the Act is not optional.
Following it correctly protects both owners, ensures construction is carried out safely, and creates a legal record that can be invaluable if disagreements arise.
What Is a Party Wall?
A party wall is any wall that stands on the land of two owners and forms part of at least one building. This includes the walls separating terraced or semi-detached houses. A wall entirely on one owner’s land can also be considered a party wall if it is used by two or more owners to separate their buildings, something commonly seen with older properties or adjoining outbuildings.
The Act also applies to:
Party fence walls
These are walls built on the boundary line that are not part of a building structure, such as garden walls separating two properties.
Party structures
These include floors and ceilings between flats or maisonettes where different owners hold the spaces above and below.
Boundary walls
Any wall built right on the line dividing two properties may fall under the Act, depending on how it is used.
Understanding these definitions is crucial because many homeowners are surprised to learn that garden walls, shared structural floors, or even parts of a property they assumed were private are actually controlled under the Act.
When the Party Wall Act Applies
The Act applies in three main categories of work. If your planned construction falls into any of these, you must serve a formal Party Wall Notice before work begins.
1. Work to an existing party wall or party structure
This includes a wide range of tasks, from structural alterations to relatively small adjustments that affect the wall’s integrity. Examples include:
• Cutting into a party wall to insert steel beams for loft conversions or extensions
• Removing chimney breasts attached to the shared wall
• Installing a damp-proof course
• Raising or thickening the wall
• Rebuilding or repairing major sections of the wall
• Demolishing and reconstructing a shared boundary wall
2. Building a new wall at or on the boundary
If you intend to build a new wall directly on the boundary line (the line of junction), whether it is to become a party wall or not, the Act requires notice. This applies to new extensions, garages, garden walls and replacement boundary structures.
3. Excavating close to a neighbouring structure
Excavation is covered when it is:
• Within three metres of a neighbouring building and deeper than its foundations
• Within six metres if the excavation intersects an imaginary 45-degree line extended downward from the neighbour’s foundation level
Excavations for new foundations, basements, retaining walls, and drainage works frequently trigger this requirement.
Work That Does Not Require a Notice
Not all work near a boundary requires a Party Wall Notice. Minor and non-structural tasks are usually exempt, including:
• Drilling for fixtures like shelves, cabinets or wiring
• Replastering or rendering internal walls
• Repointing bricks
• Replacing like-for-like materials where the structure is unaffected
• Small repairs that do not involve changing the load-bearing capacity
However, if there is any doubt about whether a project falls within the Act, it is always safer to consult a surveyor before beginning.
The Notice Process Explained
Serving notice correctly is the first legal requirement for complying with the Party Wall Act. There are three types of notice:
Party Structure Notice
Used when work directly affects an existing party wall or structure. Must be served at least two months before work begins.
Line of Junction Notice
Used when building a new wall on or at the boundary. Also requires two months’ notice.
Notice of Adjacent Excavation
Used when excavation will take place near neighbouring structures. Requires at least one month’s notice.
What the notice must include:
• The building owner’s name and address
• The address where the work is taking place
• Clear details of the proposed work
• The planned start date
• Drawings or technical specification (recommended but not mandatory)
Providing accurate, transparent information reduces the possibility of misunderstandings or disputes later.
How Neighbours Can Respond
Once notice is served, the adjoining owner has 14 days to reply. Their options are:
Consent
This allows the building owner to proceed once the notice period expires. Although no Party Wall Award is required, both parties should still record the pre-work condition of the adjoining property to avoid later disputes.Consent with conditions or a counter notice
The neighbour may request additional work for their benefit, such as raising their side of a wall at the same time. In these cases, costs may be shared.Dissent
If the neighbour dissents or simply does not reply within 14 days, a dispute is considered to have arisen under the Act. Surveyors must then be appointed.
The Surveyor and the Party Wall Award
If there is dissent, the Party Wall process moves to the surveyor stage. The building owner and the neighbour can either appoint one surveyor jointly (an Agreed Surveyor) or appoint separate surveyors. If two surveyors cannot agree, they appoint a Third Surveyor to settle the matter.
Surveyors are impartial. Their job is not to represent either party, but to ensure the work is planned and carried out fairly and safely.
Their responsibilities include:
• Reviewing plans, drawings and construction details
• Inspecting the properties and preparing a schedule of condition
• Determining how work should be undertaken to minimise risk
• Agreeing access rights for workers
• Creating the Party Wall Award
• Revisiting the site after works to check for damage
The Party Wall Award (sometimes called a Party Wall Agreement) sets out:
• What work is authorised
• How and when it must be carried out
• Working hours
• Protection measures (supports, temporary works, insulation etc.)
• Access arrangements
• Procedures for dealing with damage
• Surveyor fees and who pays them
The Award is legally binding and must be followed precisely.
Costs and Who Pays
In almost all cases, the building owner proposing the works must pay:
• Their own surveyor’s fees
• The adjoining owner’s surveyor fees
• Any fees for a Third Surveyor (if involved)
• Compensation for any damage caused by the works
Typical costs:
• Single Agreed Surveyor: £700 – £1,200
• Two surveyors: £1,400 – £3,000+ depending on complexity
If the adjoining owner requests additional work for their benefit, they may contribute to that portion of the cost.
Access Rights Under the Act
The Party Wall Act grants building owners the right to access neighbouring property when reasonably necessary to carry out the authorised works. However:
• At least 14 days’ notice must be given
• Access must be at reasonable times
• Inconvenience must be minimised
• Any damage must be repaired at the building owner’s cost
Ignoring the Act: Risks and Consequences
Failing to follow the correct Party Wall procedure can lead to:
• Court injunctions halting work immediately
• Liability for damage, even if caused accidentally
• Insurance claims being rejected
• Legal costs for both parties
• Complications when selling the property
Often, the cost of putting things right afterwards greatly exceeds the cost of doing things correctly from the start.
Common Misunderstandings About the Act
Several misconceptions frequently cause avoidable problems:
• Verbal consent is not legally valid
• Garden walls on a boundary may be party fence walls under the Act
• Neighbours cannot refuse simply because they dislike the project
• Access is not automatic without surveyor direction
• Excavation rules apply even when foundations seem shallow
Clear communication and proper documentation remove most of these issues.
Role of Conveyancers and Surveyors
Conveyancers highlight potential party wall issues during property transactions and ensure relevant documentation is available to future buyers. Surveyors handle notice preparation, technical assessments, and Awards. Together, they provide a complete framework of legal and practical protection, ensuring compliance and reducing the risk of disputes.
Practical Tips for Homeowners
• Speak to neighbours informally before serving notice
• Factor two to three months into your project timeline for the process
• Use an experienced Party Wall surveyor
• Keep thorough records of notices and correspondence
• Take photographs of both properties before works start
• Never begin work without written consent or a Party Wall Award
Early planning makes the process smoother, avoids legal complications, and helps maintain positive neighbour relationships.