When a building fails, how far is the engineer liable?

Engineers sign off drawings and calculations, and are named as supervisors in building permit applications. When something goes wrong, the injured party, the developer and the authorities usually start with those signatures.

This guide explains the routes by which an engineer may be held liable, what each turns on, and how an engineer can protect themselves before taking on the job.

On which fronts can an engineer be liable?

• Civil: compensating the client, the building owner, or third parties who suffered loss.
• Criminal: where design or supervision departs from professional standards in a way likely to cause danger, even before anyone is hurt, and more seriously where someone is seriously injured or killed.
• Professional: a complaint to the Council of Engineers, which can lead to suspension or revocation of the licence.

The three are separate, and the outcome of one does not end the others. Settling the civil claim, for example, does not stop a criminal case or a professional inquiry.

Civil liability: who can claim from the engineer?

A client who contracted directly with the engineer can claim under the contract where the design or supervision fell short of what was agreed or of professional standards. Third parties with no contract, such as a buyer, a tenant or a neighbour, can claim in tort if they prove the engineer was negligent and the negligence caused the loss.

Where the engineer is an employee of a design firm or contractor, the employer is jointly liable for torts the engineer commits in the course of employment, and having paid, the employer may recover from the engineer.

Courts usually ask whether the engineer met the standard expected of engineers in that field: whether the soil investigation was adequate, whether calculations followed current standards, and whether key stages were actually inspected.

When is an engineer criminally liable? Must someone be hurt first?

No. The Criminal Code has a specific offence for professionals who design, supervise or carry out building work and fail to follow the rules or methods that should be followed, in a way likely to cause danger to others. The offence is committed once the conduct is likely to cause danger. No one has to be hurt first.

The Supreme Court convicted two engineers over the collapse of a post office building. The design engineer left out the details of the beam-to-column joints and let the contractor draw the details. The supervising engineer, who was required to supervise daily, left non-engineers in charge and visited only once a month. The court held that both had failed to follow professional standards. In the same matter, the engineering licensing committee of the Council of Engineers suspended the designer's licence for six months.

If the failure causes serious injury or death, the engineer may also be prosecuted for negligently causing it. No intent is needed. It is enough to show the engineer failed to take the care that a person in that position should take, given their situation and the circumstances, when they could have done so.

For an engineer, "situation and circumstances" means a professional's standard, not an ordinary person's, so engineers are expected to take greater care in matters within their professional knowledge. Civil and criminal law use different words for negligence, but both measure the engineer against professional standards.

After a collapse or a death, investigators will call for the drawings, calculations and supervision records at once. An engineer should take legal advice before giving a first statement, because that statement stays on the file for the whole case.

What can the Council of Engineers do?

Controlled engineering work requires a licence under the Engineers Act. Anyone harmed by or aware of a breach of professional ethics can complain to the Council of Engineers. Outcomes range from a warning or probation to suspension or revocation of the licence. For a practising engineer, suspension hits income directly and harms reputation longer than a civil case.

What is said to the Council should be consistent with the defence in the civil and criminal cases, since a statement given on one front may be used on another.

Named as supervisor but never on site: still liable?

This is the most common risk. Some engineers lend their name as supervisor on a permit application without actually supervising. When damage occurs, not having been on site is no defence. On the contrary, it is evidence that the engineer did not take the care the role required.

The Supreme Court has held that engineers who signed consent to act as supervisors, on which the permit was issued, had a duty to supervise. Having failed to attend, so that the building was built otherwise than as permitted, they could not say the deviation was not their act, and were treated as joint offenders under the Building Control Act.

If you stop supervising partway, give written notice to the developer and notify the local authority under the building control procedure, so your name comes off work you no longer supervise.

How can engineers protect themselves?

• Use a written engagement stating clearly which parts you design, which stages you supervise, and what you are not responsible for.
• Keep the data behind the design, such as soil investigation results, and the reasons for the calculation method chosen.
• Record every site inspection with photographs and the points raised with the contractor.
• When the contractor or owner orders changes to design or materials, ask for it in writing and record your view if you disagree.
• Consider professional indemnity insurance with limits suited to the size of work you take on.
• Do not sign documents for work you did not do or did not actually supervise.

This page is general information, not advice on your situation. An engineer's liability depends on the contract, the scope of work and the facts of each case. If damage has already occurred, take legal advice before giving a statement to investigators, insurers or the Council of Engineers.