Don't Let Your Extension Go To The (Party) Wall

Anyone who has considered building an extension will appreciate that neighbours play an important part in the planning process. Are you also aware that because building works can cause damage to a neighbour’s buildings and interrupt the neighbour’s own use and enjoyment of a party wall or structure, that in certain circumstances you are required by law to keep your neighbours informed and that they have certain rights?

You need to comply with the terms of the Party Wall etc. Act 1996 (PWA) where you intend to:

  • work on existing party walls or structures
  • construct a new wall or structure at or astride the boundary line with an adjoining property, or
  • excavate within 3 or 6 metres of an adjoining building or structure (depending on the depth of the works)

The PWA provides a framework to enable neighbours who share a boundary to carry out building works and provides a dispute resolution procedure to protect the interests of the adjoining owner, while giving you as the building owner the rights you need to carry out the works.

What is a party wall?

A party wall is a wall that forms part of your building and stands on the boundary between your land and the adjoining owner’s land. The wall may be part of one building or two or more separate buildings. A wall will also be a party wall if it stands entirely on your land and the adjoining owner has a building that is enclosed by that same wall. A wall built entirely on your land is not a party wall.

What is a party fence wall?

A party fence wall is a wall that stands on the boundary, but has no buildings attached to it, for example a garden wall.

What is a party structure?

A party structure applies to all party walls and also to horizontal party structures (such as floors or ceilings) between, for example, two adjoining flats or maisonettes.

What are your obligations?

Your specific rights and obligations as the building owner depend on the nature of the proposed works. However, in relation to all works you are required to:

  • Serve notice on the adjoining owner.
  • Exercise reasonable care when carrying out works.
  • Pay all expenses (save for certain exceptions) relating to the works.
  • Compensate any adjoining owner for damage to property caused by the works (except where works to the party wall or party fence wall were made necessary by defects or want of repair).
  • Avoid causing unnecessary inconvenience to an adjoining owner during the works.
  • Commence the works within 12 months of the date of the notice and with due diligence (otherwise you risk losing the rights to which the notice relates).
  • Carry out the works in accordance with the plans, sections or particulars agreed between you and adjoining owner or, if there is a dispute, in the manner set out in the party wall award.

What are the adjoining owner’s rights?

The adjoining owner cannot prevent you from carrying out works that you are entitled to undertake. The adjoining owner only has the right to raise a dispute in response to your notice, which will trigger a requirement for a party wall surveyor to make an award that will govern the manner in which the works are carried out and deal with compensation.

In certain situations, the adjoining owner may require you (by way of a counter-notice), to incorporate additional works, for example works to underpin or strengthen the foundations of the adjoining owner's buildings.

What are the adjoining owner's obligations?

After receiving sufficient prior notice, an adjoining owner must allow you and your workmen access to its land for the purpose of executing any work.

If the adjoining owner requires you to carry out additional works during the planned works to an existing party wall, or consents to the construction of a new party wall, the adjoining owner may be obliged to contribute to the cost of the works.

An adjoining owner who requires additional works to be incorporated into your works to an existing party wall must serve a counter-notice within one month of service of your original notice.

What notice must you give?

You must give notice to all adjoining owners of any works that will be caught by the provisions of the . The notice requirements vary depending on what the work involves.

Existing walls

If you plan to carry out works to an existing party wall or party fence wall, you must give the adjoining owner two months' notice before the works commence. Alternatively, you may obtain the adjoining owner's prior written consent to the works.

In response the adjoining owner may:

  • Serve a counter-notice within one month. In those circumstances, you may consent to the adjoining owner’s counter-notice within 14 days, if not, there is a dispute.
  • Give written notice of consent within 14 days.
  • Refuse to consent in writing.
  • Do nothing and a dispute will be deemed to arise after 14 days.

New walls or party fence walls

You must give adjoining owners one month's notice of an intention to build a new wall or party fence wall on the line of junction (that is, the boundary). The notice should indicate the desire to build and describe the intended wall.

If you wish to build a wall astride the boundary, you are required to obtain the adjoining owner’s consent. The adjoining owner has 14 days to give written consent. If the adjoining owner consents, the new wall or party fence wall may be built half on each owner's land, with the costs being divided between the two owners, depending on the benefits each will derive from the new structure.

If you fail to obtain the adjoining owners' consent within 14 days of its notice, you must build the wall entirely on your own land at your own expense.

If you intend to build entirely on your land but the footings or foundations will extend over the boundary you may proceed once the notice has expired unless the adjoining owner objects. You will be responsible for the costs of building and will be required to compensate the adjoining owner for any damage caused by the works. If the adjoining owner objects, you are required to follow the dispute resolution procedure.


You must give adjoining owners one month's notice of your intention to carry out any works that sink foundations or other structures within either:

  • Three metres of the adjoining owner's buildings, if the proposed foundations would be deeper than the adjoining owner's foundations.
  • Six metres of the adjoining owner's buildings if any part of the proposed structures (typically foundations) would be dissected by a line drawn downwards at a 45 degree angle from the nearest part of the adjoining owner's.

You are obliged to underpin or strengthen the foundations on the adjoining owner's land if required to do so by the adjoining owner.

If an adjoining owner does not consent to the building owner's notice within 14 days, there will be a dispute.

It is sensible to discuss your proposed works with adjoining owners before you serve any notice. Then, when the relevant notices are served, the adjoining owners may be more willing to consent.

What happens if there is a dispute?

The parties can jointly appoint an agreed party wall surveyor to make an award, or can each appoint their own party wall surveyor who will then select a third party wall surveyor. The agreed party wall surveyor should not be the person you have employed to supervise your building works. The surveyor's appointment should be made in writing.

If a third party wall surveyor has been appointed, either party, or a surveyor appointed by one of the parties, may refer to that third surveyor any dispute.

The party wall surveyor may resolve any matter that is connected to the works and is in dispute between you and adjoining owner. The party wall surveyor's decision is known as an award.

Can you appeal against the party wall award?

The award is final and binding and may only be overturned by an appeal to the county court. Either party may appeal. The appeal must be made within 14 days of the award being served.

The county court may rescind or modify the award and may make a costs order as it "thinks fit".

What payments are made under the PWA?

Generally, you will be responsible for the costs of the works as they will be for your benefit.

The party wall surveyor's jurisdiction extends to deciding who will pay the costs of the award, which will include the party wall surveyor's costs for inspecting the works, in making and obtaining the award and in dealing with any other matters relating to the award. It is usual for you to pay all the costs associated with the award, including the surveyor's reasonable costs.

As the PWA allows you to act in a way that (but for the Act) would constitute trespass or nuisance, you are required to exercise your rights without causing "unnecessary inconvenience" to the adjoining owner or occupier and to compensate adjoining owners or occupiers for any damage or loss they might experience during or as a result of the works.

What happens if you fail to comply with the PWA?

Your obligations under the PWA  are statutory. If you carry out works without complying with those statutory obligations, you:

  • Will be deprived of the PWA's protection. Any damage or loss sustained by an adjoining owner as a consequence of works carried out without first giving notice, obtaining consent or obtaining a valid award under the PWA is actionable in private nuisance. Additionally, you may be liable in trespass.
  • May be liable for breach of statutory duty.

An adjoining owner may seek an injunction to stop you starting or continuing with the work if you refuse to follow the correct PWA procedure. In such cases, injunctions are usually granted in favour of the adjoining owner. In some cases an injunction is not appropriate, for example, where your works have already reached completion. In that situation, the adjoining owner may seek compensation on the basis of your failure to serve a notice.

What happens if either party fails to appoint a surveyor?

If one party will not consent to the appointment of an agreed party wall surveyor and then fails to appoint a party wall surveyor of its own, the other party can make an appointment on its behalf.

What happens if the adjoining owner refuses to give access?

If you are entitled to carry out works and have given 14 days’ notice of your proposed entry, it is an offence for the adjoining owner to:

  • Refuse a person (including a party wall surveyor) access to its land to carry out works.
  • Obstruct a person from carrying out works.
First published Jul 2014
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Although correct at the time of publication, the contents of this article are intended for general information purposes only and shall not be deemed to be, or constitute legal advice. We cannot accept responsibility for any loss as a result of acts or omissions taken in respect of this article. Please contact us for the latest legal position.