Basement Developments: Your Rights When a Neighbour Digs Down

Basement developments remain popular across London. A basement excavation removes ground that has supported your foundations for a century, often within a couple of metres of your walls.

Under the Party Wall etc. Act 1996 your neighbour must notify you before excavating close to your building, say how they will safeguard your foundations, and compensate you for damage.

What rights do you have when a basement is proposed next door?

Three systems apply, on different timetables.

Planning. Councils must publicise an application. For most householder schemes that means a site notice displayed for at least 21 days or a letter to adjoining owners, and representations cannot close earlier than 14 days after publication on the council’s website. Object before permission is granted, and check the local plan, because basement policy varies between boroughs.

Party wall and common law. Planning permission does not remove the need to comply with the Act, and the reverse is equally true. Underneath both sit your rights in nuisance, trespass and negligence, which take over if your neighbour ignores the Act.

When does a basement excavation need a party wall notice?

Section 6 of the Act sets two distance tests. If either is met, notice is required.

• The 3 metre rule. Notice is needed where your neighbour proposes to excavate, or excavate for and erect a building or structure, within three metres measured horizontally from any part of your building, and any part of that work will go to a lower level than the bottom of your foundations.
• The 6 metre rule. Notice is also needed where the work is within six metres horizontally and any part of it will meet a plane drawn downwards at 45 degrees from the bottom of your foundations.

Most London basement schemes engage the 3 metre rule. Deeper digs on wider plots catch the 6 metre rule.

How much notice must you get?

Section 6(5) requires the notice at least one month before excavation begins. It must state whether your neighbour proposes to underpin or otherwise safeguard your foundations, and section 6(6) requires plans and sections showing the site and depth of the excavation.

If you do not consent in writing within 14 days, section 6(7) treats you as having dissented and a dispute is deemed to have arisen, which moves matters into the surveyor procedure.

Can you require your neighbour to protect your foundations?

Yes. Section 6(3) provides that the building owner may, and if required by the adjoining owner shall, at his own expense, underpin or otherwise safeguard your foundations so far as necessary.

What should the party wall award cover for an excavation?

Surveyors resolve the deemed dispute by award under section 10. Agree a single surveyor, or each appoint your own. Press for the award to cover:

• A detailed schedule of condition of your property, with photographs, before work starts
• The sequence and method of excavation, including underpinning in short bays
• Movement monitoring, with trigger levels and an agreed response if exceeded
• Working hours and controls on noise, vibration and dust
• Insurance and the professional fees your neighbour is liable for

Section 10(13) leaves the surveyors to decide who pays their costs, and where works are solely for the building owner’s benefit the building owner normally pays. If you disagree, either party has 14 days beginning with the day the award is served to appeal to the county court under section 10(17). After that it is conclusive under section 10(16).

What if the basement works damage your property?

Section 7(2) requires the building owner to compensate any adjoining owner and occupier for loss or damage resulting from work executed under the Act. Section 7(1) separately prohibits causing unnecessary inconvenience.

Cracking, distorted openings and settling floors are the usual complaints. Without a schedule of condition, it is difficult to prove the damage was not already there.

Section 6(10) adds that nothing in section 6 relieves the building owner of liability for injury caused by the work. Where the contractor is at fault, the claim may lie in construction disputes instead, and our property litigation team will identify who to pursue.

What if the excavation has already started without notice?

In Power and Kyson v Shah [2023] EWCA Civ 239 the Court of Appeal held that the section 10 procedure is not engaged where no notice was served, so you cannot simply appoint a surveyor and produce an award. Your remedies are the common law claims in trespass, nuisance and negligence, and an injunction where appropriate. The government’s explanatory booklet confirms the Act has no enforcement procedure for a failure to serve, and that an adjoining owner can seek to stop work by injunction.

Take these steps in order:

1. Get an independent schedule of condition prepared immediately, with photographs
2. Write to your neighbour saying notice was required under section 6
3. Take advice on an injunction while work is under way
4. Keep a dated record of cracking, vibration and noise

How we can help

We act for adjoining owners and developers on basement excavation disputes: party wall notices and awards, appeals under section 10(17), injunctions to stop unnotified works, and damage claims in nuisance and trespass. We also advise on the boundary and neighbour disputes these schemes bring with them.

Call us on 020 7485 8811 or fill in the contact form below.