Cracks at the Party Wall
A 1930s Grade 3 shophouse in Sham Shui Po is being converted: the rear extension is being demolished, a new lift shaft and steel frame inserted. The party wall is shared with a four-storey 1950s building. Demolition began under an approved plan that specified temporary shoring and monitoring of the party wall at three points. The shoring was never installed and there are no monitoring records. A neighbour reports 3 mm diagonal cracks and a 25 mm out-of-plumb on the boundary wall. Your firm's technically competent person has been on site two half-days per week; the contractor's site records are missing for nine days. The contractor says the cracks pre-date the works. The client wants the cracks patched and the works continued to protect the opening date.
1. What are your immediate actions, and what statutory notifications are required?
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Stop. The client's instruction to patch and continue must be refused in writing, because the combination of no shoring, no monitoring, fresh cracking and 25 mm of out-of-plumb is a potential danger to the adjoining building and to the public.
Immediate actions: halt all demolition and excavation in the affected area and any works that load or support the party wall; secure the site perimeter with hoarding and restrict access; prohibit anyone from working beneath or against the affected wall; photograph and video the condition with a date reference; and make a contemporaneous file note of the decision and the reasons.
Engage the registered structural engineer, and the registered geotechnical engineer if ground or slope stability is involved, to carry out an urgent appraisal of the party wall and the adjoining building. Install monitoring immediately - crack gauges, tell-tales and tilt plates - with a defined frequency and trigger and action levels agreed with the engineer.
Statutorily, notify the Buildings Department without waiting for the neighbour to complain: a building that appears to be dangerous engages the Buildings Authority's dangerous-building powers, and the Authority can act quickly and at the owner's cost. Inform the owner and, where relevant, the owners' corporation of the adjoining building, and carry out a joint condition survey with them as soon as possible to record what is pre-existing and what is not. Notify the works insurance and professional indemnity insurers. If there is any risk to life, involve the Fire Services Department and the police.
The absence of a pre-works joint condition survey is a significant gap and should be acknowledged, not concealed.
2. Assess the adequacy of site supervision and the professional exposure of the authorised person and the firm.
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The supervision appears inadequate for the risk, and the correct response is a candid internal review rather than a defence of the record.
A demolition adjacent to a party wall, with temporary works and monitoring specified on the approved plans, is high-risk activity. Site supervision should be planned around it: a supervision plan with technically competent persons of the appropriate grade, defined frequencies, hold points before demolition and before temporary works are covered up, and documented checks. Two half-days per week, with no evidence that the shoring was ever checked before demolition, and nine days of missing contractor records, suggest the hold points were not enforced.
The authorised person's statutory role includes coordination and supervision of the works, and the supervision obligations attach to the firm as well as to the individual. Failure can lead to disciplinary action against the registered person and loss of registration, quite apart from negligence liability to the client and to third parties.
The firm cannot rely on the contractor's own supervision to discharge its obligations. Reconstruct the supervision record from diaries, emails, photographs and site instructions, and write down honestly what was and was not done. Notify the insurer. Do not backdate, 'reconstruct' forms or amend the supervision records - that is a far more serious matter than the original lapse.
If the investigation shows the firm's supervision fell below the standard reasonably to be expected, advise the client to seek independent legal advice, and consider whether the firm must cease acting on the project.
3. The client wants to patch the cracks and recover the cost from the neighbour or the contractor. How should the contractual and evidentiary issues be handled?
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Separate the three questions: what caused the cracking, who bears the cost, and what must happen before the works resume.
Cause and evidence: the contractor says the cracks pre-date the works, but there is no joint pre-works survey, no monitoring data and missing records, which makes the contractor's position difficult to sustain and equally undermines any claim the client might bring. Preserve evidence now: a joint survey with the adjoining owner, dated photographs, engineer's report, and if necessary an independent expert appointed on a joint basis. Do not carry out cosmetic patching before the survey - patching destroys the evidence and may aggravate the movement by hiding it.
Contractual: the contractor departed from the approved plans by not installing the specified shoring. That is a breach of contract and a departure from approved works, and the architect should instruct immediate compliance and record the instruction. The contract's indemnity and insurance provisions commonly cover damage to adjoining property caused by the contractor's negligence; check the wording, notify the insurers and do not admit liability on the client's behalf. Hong Kong has no general party-wall statute equivalent to the United Kingdom's; rights and duties arise from the deeds and leases, the Buildings Ordinance, and the common law of nuisance and negligence, so the neighbour's claim needs legal analysis, not assumption.
Recovery from the neighbour is unlikely to succeed if the works caused the movement; the realistic target is the contractor and its insurers.
Finally, advise the client that resuming before the engineer's clearance and the reinstated shoring would expose directors and the authorised person to far greater risk than any delay to the opening date.