What Is a Party Wall? Everything You Need to Know

what is a party wall

What Exactly Is a Party Wall?

A party wall is a wall that straddles the boundary of two adjoining buildings or properties. The 1996 Party Wall Act reveals two kinds of party walls.

The first is known as a Type A wall. Section 20 (a) of the act describes a party wall as “a wall which forms part of a building and stands on the lands of different owners to a greater extent than the projection of any artificially formed support on which the wall rests.”

To put it simply, a Type A party wall straddles the boundary line of two buildings either equally or more to one side.

Examples of Type A walls include the adjoining walls of a terraced or semi-detached building. In addition, a wall on the boundary dividing two gardens could also be a Type A wall.

The second type of party wall is Type B. This kind of wall doesn’t sit on the boundary line of the two properties, but it’s wholly on the property of one owner. However, only parts of the wall are used to separate the buildings. In that case, the parts used for separation are considered a party wall, and other parts that don’t directly separate the buildings aren’t seen as party walls.

Building an extension to or changing a party wall can be a controversial and contentious affair, especially if it’s a Type B wall.

That’s where the Party Wall Act comes to play. So let’s find out what it’s all about.

What’s the Party Wall Act?

The Party Wall Act is a law enacted in England and Wales in 1996 to spell out the procedures for making changes to shared walls.

The legislation is generally traced back to the Great Fire of London. It forced both builders and legislators to reexamine regulations around party walls to prevent the spread of fire across adjacent properties.

So before you begin any kind of work on a shared wall, it’s worth checking out whether the Party Wall Act covers it. Here’s what the act covers:

  • Breaking down and rebuilding a shared wall
  • Adding an extension
  • Increasing the thickness of the wall
  • Underpinning
  • Cutting into boundary walls
  • Excavation and foundation work
  • Adding a damp-proof course

Below are some areas that the Party Wall Act doesn’t cover:

  • Plastering
  • Adding a wallpaper
  • Electrical wiring
  • Shelf-fitting
what does party wall mean

Do I Need a Party Wall Agreement?

A party wall agreement is a legal agreement between you and your neigbour(s) who may be affected by your modification to the party wall. You’ll need it for the works covered under the Party Wall Act.

The agreement typically spells out precisely the works you want to undertake and how the work will progress. To get started, you’ll have to serve your adjoining owners with a party wall notice.

What’s a Party Wall Notice?

A party wall notice is a written document that clearly outlines everything about the work you intend to do on the shared wall.

We recommend that you serve party notices at least two months before work begins, as this would give your neighbours the time to review your notice and give their consent. The earlier your message goes, the earlier you can reach an agreement and start your construction work.

In addition, always serve valid party notices. Don’t withhold or leave out any vital information. If your adjoining owners discover any deceit in your message, they can cancel the agreement, even if it’s already been signed. Further, they can hire a solicitor and take legal action against you.

Every party notice should have the following:

  • Names, contacts, and addresses of all owners
  • The kind of work you want to carry out
  • When you intend to commence the work

The final agreement should bear the signature of all the owners or their appointed third parties. In some cases, surveyors may act as representatives of owners.

From the Party Wall Act, there are three kinds of party notices:

  • Section 1 – Line of Junction Notice
  • Section 3 – Party Structure Notice
  • Section 6 – Adjacent Excavation Notice

Let’s explore each in a bit of detail.

Section 1 – Line of Junction Notice

This kind of party notice is for boundaries where there are no buildings yet. However, a boundary wall, such as a brick wall, could separate the properties. It’s important to note that partitions like timber fences aren’t considered boundary walls in this context.

This notice is to help you and your neighbours reach an agreement regarding the boundary line and the position and type of wall adjustments you want to make.

Section 3 – Party Structure Notice

This kind of notice covers any change you want to make to an existing party structure or fence wall. Examples of works covered under this section include taking out a chimney breast or adding beams to a party wall.

You have to give notice as early as possible for these kinds of work. At the very minimum, provide notice from two to three months.

Section 6 – Adjacent Excavation Notice

As the name suggests, this kind of notice is for any kind of excavation works on or close to a party wall. Some think this notice is only needed when the excavation work is right along the boundary line. However, the Party Wall Act states that you should notify owners when:

  • Excavation is lower than the existing foundation and within three meters of an owner’s building.
  • Excavation is within six meters of an adjoining building and is at a 45-degree plane below the foundations.

Because excavation and foundation works can affect the structural integrity of a building, it’s essential to be thorough in describing how the excavation work will be carried out. We recommend adding images, graphs, and diagrams to make the process straightforward and transparent.

party wall definition

What Work You Must Notice Your Neighbours About

As mentioned earlier, you must tell your adjoining owners about all works covered under the Party Wall Act.

In general, any work that involves building on your boundary line, adjusting or modifying an existing party wall, and excavation or foundation works demands that you give your neighbours proper notice. Examples of such works include building a loft, removing a chimney, and extending a wall.

If you do such works without your adjoining owners’ prior approval, they can take you on in court.

What Work You Don’t Need to Notice Your Neighbours About

Of course, you don’t need to tell your adjoining owners about everything. Minor works like plastering, wallpapering, drilling, and wiring don’t require party notice of any sort.

What Will Happen When My Neighbour Gets My Party Wall Notice?

You have to send your neighbour an official notice in writing. You can expect the following once your neighbour receives your party notice:

  • Your neighbours will respond in writing within 14 days whether they agree or disagree with your request.
  • If your neighbours don’t reply, it means they’ve automatically dissented to your notice. They’ll be required to provide a surveyor within the next ten days.
  • If they don’t appoint a surveyor, you can nominate one for them.
  • If your neighbours agree with your request, you can both appoint one surveyor.
  • The surveyor(s) will look over your plans to make sure that they won’t affect the party wall in the long run.
  • The surveyors will visit the structure in question and assess and record its state before work commences.
  • Once you reach an agreement, the surveyors will serve a Party Wall Award or contract that clearly outlines how the work will progress and what happens when things go wrong.

What Will Happen When I Don’t Serve a Party Wall Notice?

There are many potential consequences when you fail to serve a party wall notice. For starters, you won’t have any protection against false accusations of damage.

For instance, neighbours can accuse you of significant damage to their property as a result of your work. However, as long as you have the party notice and the schedule of conditions prepared by a surveyor, you can defend yourself.

Moreover, if you fail to serve notice, your neighbour can take you to court, seeking an injunction on your construction. This can lead to significant delays. Besides, the legal fees on both sides will be your cost to bear.

Ultimately, starting construction on a party wall without giving your neighbour prior notice can lead to bad blood between the two of you. Moreover, this mistrust and contention can affect further projects you might undertake on the party wall.

Who’s Responsible for the Party Wall Notice Fees?

If you’re the person who plans to carry out the work, then you’re the one who’ll take care of the costs associated with the notice.

When adjoining owners consent to the work, your fees will be minimal. However, when the owners disagree or don’t respond, you’ll have to appoint surveyors on both sides to help resolve the impasse.

Those costs can run into thousands of pounds. In addition, if you take the matter to court, that’ll also incur extra charges.

How to Prevent and Resolve Party Wall Disputes

If you face a dispute regarding your party wall notice, you’ll need to find ways to resolve it amicably. First of all, it’s best to sit with your neighbours and have a conversation.

Explain to them precisely what you intend to do. In most cases, neighbours reject party wall modifications because they don’t trust the person carrying out the project. This is where your relationship with your neighbours will come in handy.

If they don’t accept your explanation, you’ll have to play by the book. On both sides, you’ll appoint surveyors, and they’ll look at the party wall in question as well as your plans to reach a conclusion.

If there’s still no resolution, you can contact a law firm that has expertise and experience in such matters to help you.

Is There a Difference Between a Party Wall and a Boundary Wall?

Yes. Although the terms “Party Wall” and “Boundary Wall” are often used interchangeably, the Party Wall Act makes the difference clear.

A boundary wall is a wall that sits wholly on the land of one owner. Its piers are also on that same land.

In contrast, a party wall lies astride the boundary line of two properties.

Do I Need a Party Wall Surveyor?

It depends. If your adjoining owner agrees to your party notice, you may not need to appoint a surveyor. However, if they disagree with your request, you’ll have to nominate surveyors on both sides to help resolve the dispute.


In some cases, you and your neighbours can agree to choose one surveyor in a bid to reduce cost. However, be sure to select a competent, impartial surveyor who’ll be objective with the work.

Conclusion: What is a Party Wall?

In summary, we’ve looked at the Party Wall Act and what you’re supposed to do if you ever want to make adjustments to your party walls.

Write to your neighbours to inform them what you intend to do and how you want to do it. If your neighbours disagree or don’t respond, hire a surveyor to help you out.

If you need to, you can hire a top-notch lawyer to help you sort the issues.

Ultimately, be sure to build good relationships with your neighbours, as that’ll make it easy to communicate your intentions.