What Are Party Walls and What Do You Need to Know When Renovating a House?

A party wall is a wall or structure shared by two properties, or in some cases a wall on one owner’s land that is used by both properties. 

If you are renovating a house in England or Wales, you may need to follow the Party Wall etc. Act 1996 before starting certain works. This can apply when altering a shared wall, building on a boundary or excavating close to your neighbour’s foundations. 

The Party Wall etc. Act 1996 came into force on 1 July 1997, meaning the legislation has now been in place for almost three decades. It applies throughout England and Wales.

The government’s impact assessment also estimated that around 63,840 party wall notices were served in a year in its modelling, demonstrating how common party wall procedures can be in the UK building sector.

Understanding the rules early can prevent delays, disputes and unexpected costs later in your renovation.

Key Takeaways

• Not every renovation needs a party wall agreement. The rules normally apply to specific types of structural work, boundary work and excavation rather than ordinary decorating or minor alterations.
• You may need to serve notice before work starts. For work to an existing party wall, the usual notice period is at least two months. For certain new walls and excavation, it is generally one month.
• You do not automatically need a party wall surveyor. If you and your neighbour agree to the proposed work in writing, a surveyor may not be necessary. If there is a dispute, however, surveyors can be appointed to resolve it under the Act.

What Is a Party Wall?

A party wall is most commonly a wall shared by two neighbouring properties.

This is particularly common with terraced and semi-detached houses. A wall can be a party wall even where the boundary does not run directly through the centre of it.

The Party Wall etc. Act 1996 also covers certain other structures such as floors or walls separating different parts of buildings, as well as certain boundary walls.

A garden wall can also fall within the definition of a party fence wall, although an ordinary timber fence does not.

The Act applies in England and Wales. Different rules apply in Scotland and Northern Ireland.

What Falls Under a Party Wall?

A wall shared by two properties – commonly found between semi-detached and terraced houses.

A wall standing on the boundary – where the wall forms part of the boundary between two properties and is used by both owners.

A party structure – this can include structures separating parts of different buildings, such as certain shared floors or walls.

A party fence wall – a masonry wall built astride the boundary and used by both properties. A normal timber garden fence is not usually a party fence wall.

Certain excavation works near a neighbour’s property – particularly where you plan to excavate within 3 metres of a neighbouring building and below the level of its foundations, or within 6 metres in certain circumstances.

Certain work to an existing party wall – such as cutting into it, removing part of it, increasing its height or thickness, or carrying out structural alterations.

Building a new wall on or near the boundary – certain new building work is covered by the Party Wall etc. Act 1996 and requires the correct notice to be served.

When Does the Party Wall Act Apply?

The Act applies to particular types of building work – and simply having a shared wall does not mean you need to serve a party wall notice every time you carry out work.

This includes work directly to an existing party wall or party structure, building a new wall on or close to the boundary, and certain excavation works close to a neighbouring building.

For example, removing a chimney breast attached to a party wall can fall within the Act. So can cutting into a party wall, making it higher or deeper, or knocking down and rebuilding part of it.

Excavation can also be important during an extension or new-build project. If foundations are being dug close to and below the level of your neighbour’s foundations, party wall procedures may apply.

This is one reason why party wall considerations should be discussed during the early design stages rather than after construction has already been scheduled.

Do I Need a Party Wall Agreement?

If your proposed work falls under the Act, you generally need to serve the correct notice on the adjoining owner.

Your neighbour can then consent to the proposed work. If they consent in writing and there is no dispute, a formal surveyor’s award may not be required.

If they do not consent, or they do not respond within the relevant period, a party wall dispute can arise under the Act. A surveyor or surveyors can then be appointed to deal with the matter and prepare a party wall award.

This means that calling every situation a “party wall agreement” can be misleading. The correct process depends on the work being proposed and how the adjoining owner responds.

Do You Need a Party Wall Surveyor?

No, you do not necessarily need a party wall surveyor.

The government guidance confirms that there is no requirement to appoint a surveyor simply because you are serving a party wall notice. If your neighbour agrees to the proposed work, you may be able to proceed without appointing surveyors.

However, a surveyor becomes important if there is a dispute under the Act.

You and your neighbour can each appoint a surveyor, or you can agree to use a single Agreed Surveyor. The surveyor’s role is to deal with the party wall matter impartially and produce an award setting out how the works should be carried out.

For more complicated renovation projects, some homeowners choose to appoint a party wall surveyor from the outset because it gives them professional advice and helps ensure the correct notices and procedures are followed.

It is worth remembering that a party wall surveyor should be independent of the construction work itself. The government guidance states that a person already engaged to supervise the building work should not act as the party wall surveyor.

How Much Notice About a Party Wall Do You Need to Give?

For work to an existing party wall or party structure, the usual notice period is at least two months before the proposed start date.

For certain works involving a new wall on the boundary or excavation near a neighbour’s foundations, the notice period is generally at least one month.

The government’s guidance also states that a notice for work to an existing party wall is generally valid for one year.

This is why it is sensible to consider the Party Wall Act while your architect or designer is developing the plans. Leaving the process until your builder is ready to start can create an avoidable delay.

In some circumstances, your neighbour can agree in writing to allow work to start earlier, but they are not required to do so.

How Long Does a Party Wall Agreement Last?

The length of time a party wall agreement remains valid depends on the type of document involved. A Party Wall Notice is generally valid for one year, meaning the relevant notifiable work should begin within 12 months. 

Written consent from a neighbour relates to the specific notice and works described, so it should not be treated as permanent permission for future or substantially changed works. 

A Party Wall Award does not have the same simple one-year expiry rule, but it may need to be reviewed if the project is significantly delayed or the plans, structural details or construction methods change. 

If your home renovation has been delayed or your original party wall paperwork is more than a year old, it is sensible to have it reviewed by a party wall surveyor before work begins.

What Happens After a Party Wall Notice?

Once the appropriate notice has been served, your neighbour has several options.

• They can consent to the proposed work in writing.
• They can disagree with the work.
• They can also fail to respond. 

Under the Act, if an adjoining owner does not respond within 14 days in certain circumstances, a dispute is deemed to have arisen.

If there is a dispute, the parties can appoint surveyors to resolve the matter.

The surveyor or surveyors will consider the proposed works and prepare a party wall award where required. This can set out how and when the work should be carried out and what protections should be put in place for the neighbouring property.

What Is a Party Wall Award?

A party wall award is a formal document produced as part of the dispute resolution process.

It sets out the agreed or determined arrangements for the relevant building work.

It can cover matters such as the nature of the proposed works, how they should be carried out, working hours, protective measures and access for inspection.

A surveyor may also prepare a Schedule of Condition for the adjoining property before work begins.

This records the condition of the neighbouring property, often with written descriptions and photographs. 

It can be extremely useful if a disagreement later arises about whether damage was caused by the building work. The government’s guidance describes a schedule of condition as prudent, although it is not itself a requirement of the Act.

What Happens If You Start Work Without a Party Wall Notice?

If your renovation is covered by the Party Wall Act and you start work without giving the required notice, your neighbour may be able to take legal action.

The government guidance states that an adjoining owner can seek to stop the work through a court injunction or pursue other legal redress where the Act’s requirements have not been followed.

Even where you have a good relationship with your neighbour, it is better to follow the correct process.

A friendly conversation is useful, but it should not be treated as a substitute for a formal notice where the Act requires one.

Do Party Wall Rules Apply to House Extensions?

Yes, house extensions are where party wall matters commonly arise.

A rear extension may involve excavating close to the neighbouring property’s foundations. A side extension may involve construction close to the boundary. Internal alterations can also involve work to a shared wall.

The exact requirements depend on the design and construction method.

For example, simply decorating a party wall is very different from cutting into it to install structural steelwork.

The government specifically lists cutting into a party wall, removing chimney breasts and making changes to the wall’s structure among examples of work that may require notice.

Do Building Regulations and Planning Permission Apply For Party Walls?

Party wall procedures are separate from planning permission and building regulations.

Having planning permission does not mean that you have automatically complied with the Party Wall Act.

Likewise, obtaining a party wall agreement does not mean that your project has planning permission or building regulations approval.

A renovation may therefore require several different approvals or procedures.

Depending on the project, these could include planning permission, building regulations approval, structural engineering calculations and party wall procedures.

Your architect, designer or building professional should identify the relevant requirements during the planning stage.

How Much Does a Party Wall Surveyor Cost?

In London, a reasonable ballpark for a straightforward residential project is around £1,000–£1,500 for an agreed surveyor, where you and your neighbour use the same surveyor. If you and your neighbour appoint separate surveyors, the combined cost can commonly rise to around £2,000–£3,500+. 

More complex projects, such as basement excavations or work involving several adjoining properties, can cost considerably more. 

It is also worth remembering that the homeowner carrying out the work will usually be responsible for the reasonable party wall surveyor costs, including the adjoining owner’s surveyor where one is appointed.

For a typical house extension in London, we would therefore recommend allowing around £1,500–£3,000 in your budget for party wall matters, depending on how many neighbours are affected and whether they agree to use a single surveyor.

What Should You Do Before Starting a Home Renovation?

The best approach is to consider party wall matters at the same time as your architectural and structural plans.

Start by identifying whether you share a party wall or boundary with another property.

Then discuss the proposed work with your architect, structural engineer or builder.

If the work could fall under the Party Wall Act, establish which notices are required and when they need to be served.

You should also speak to your neighbour early.

A good relationship with adjoining owners can make a renovation much easier. Explaining the work before they receive formal paperwork can help avoid misunderstandings and give them an opportunity to raise reasonable concerns.

Any formal agreement should still be recorded in writing.

What Are the Most Common Party Wall Mistakes?

One common mistake is assuming that planning permission covers party wall requirements – but this is not the case.

Another common error is leaving the party wall process until the last minute.

With a two-month notice period for certain works, failing to plan ahead can affect your construction programme.

A further mistake is assuming that every renovation requires a surveyor. However, a surveyor is not automatically required simply because your project involves a party wall. If the neighbour consents and there is no dispute, the process can be much simpler.

Finally, homeowners should not assume that an informal conversation with a neighbour is enough where formal notice is required.

Final Thoughts

Party walls are an important consideration whenever you are renovating a property in England or Wales, particularly if your plans involve structural alterations, an extension, boundary construction or excavation close to a neighbouring building.

The key is to deal with the issue early.

You may not need a party wall surveyor, and your neighbour may be happy to consent to the proposed works. However, where the Act applies, the correct notice must still be served and the statutory process followed.

For homeowners, the safest approach is to discuss the proposed works with your architect, structural engineer and building contractor at an early stage. If there is any uncertainty about whether the Party Wall etc. Act 1996 applies, consider taking advice from a suitably experienced party wall professional.

Planning ahead can help protect your relationship with your neighbours, prevent avoidable delays and give everyone a clear understanding of how the renovation will be carried out.