The basement, the email notice and the cracks next door
A homeowner is building a rear extension and basement at a semi-detached house. The basement excavation will be 2.8 m deep and will come within 2.5 m of the neighbour's foundations, which are 1.2 m deep. The homeowner served a one-page 'party wall notice' by email five days ago and started digging yesterday. The neighbour calls you, as a chartered surveyor, saying cracks have already appeared in her rear wall. The builder says no award is needed because the extension is 'only single storey above ground' and the notice was 'sent electronically'. Planning permission and building regulations approval are in place.
1. Explain the statutory position under the Party Wall etc. Act 1996 and identify the breaches.
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The works engage the Party Wall etc. Act 1996. The excavation is within 3 m of the neighbour's foundations and will be deeper than those foundations (2.8 m against 1.2 m), so notice under section 6 is required. The notice must be served at least one month before excavation begins. A one-page notice emailed five days before digging, with work already started, does not satisfy that timetable. Electronic service is not a safe substitute for proper service under the Act unless the neighbour has clearly agreed to it; the statutory service provisions should be followed.
The builder's point that the extension is 'only single storey above ground' is irrelevant: the Act is concerned with the excavation and its effect on the neighbour's foundations, not merely the height of the superstructure. Planning permission and building regulations approval do not replace party wall consents or an award. Starting work before the dispute-resolution procedure is complete is a breach and exposes the owner to injunction proceedings and liability for damage.
2. What immediate advice would you give the neighbour, and what evidence should be gathered?
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I would advise the neighbour to write immediately to the owner and builder requiring work to stop until the party wall position is regularised, and to keep a copy. She should not rely on verbal assurances. She should photograph and date the cracks, note whether they are new or pre-existing, and ask for a schedule of condition or a joint inspection. If the cracks are continuing or the excavation is unstable, she should consider instructing a structural engineer and, if necessary, seeking legal advice about an injunction.
I would also advise her to check her household insurance and to notify the local authority building control team if there is a danger to the structure. She should appoint a party wall surveyor promptly; if the owner does not agree, the statutory dispute procedure can be used. I would prepare a factual note of the crack locations, dimensions and dates, but I would not tell her that the cracks are definitely caused by the excavation without further investigation. The evidence should be gathered now because the pre-works condition is already in doubt.
3. What are the consequences for the owner and how should the matter proceed from here?
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The owner should stop excavation, serve a valid notice in accordance with the Act, and allow the statutory period to run. If the neighbour dissents, the parties should appoint an agreed surveyor or each appoint a surveyor, and an award should be made before the excavation resumes. The award can deal with the time and manner of working, protection for the neighbour's foundations, and liability for damage. The owner should also check whether the builder's insurance and the owner's insurance cover excavation risks.
The neighbour's cracks should be recorded and monitored. If damage is caused by the works, the owner may be liable under the Act or in nuisance/negligence, depending on the circumstances. The owner should not assume that because planning and building regulations approvals exist, the civil obligations to the neighbour have been met. The builder's assertion that no award is needed is not a legal opinion and should not be relied on. The matter should proceed on the basis of written notices, a proper award and a pre-works condition record, not retrospective assurances.