Gibbs & Anor v Mercantile Mutual Insurance

Gibbs and Anor v Mercantile Mutual Insurance concerned a dispute between the appellants, Mr and Mrs Gibbs, and the respondent insurer, Mercantile Mutual Insurance. The Gibbs sought to recover under a home building insurance policy for damage to their home caused by a burst pipe. The insurer denied liability, alleging the damage was not covered by the policy. The matter came before the High Court of Australia.

The central legal issue before the High Court was the proper construction of the insurance policy, specifically whether the damage caused by the burst pipe fell within an exclusion clause that excluded cover for damage caused by "gradual deterioration, rust, corrosion, rot, mould or fungus". The court was required to determine whether the damage resulting from the burst pipe was a consequence of a covered event or fell within the ambit of the exclusion.

The High Court held that the damage caused by the burst pipe was not excluded by the policy. The majority reasoned that the exclusion clause applied to damage that occurred gradually over time, such as through the slow processes of deterioration or corrosion. In contrast, the burst pipe was an identifiable, sudden event, and the resulting damage was a direct consequence of that event, not a gradual deterioration. The court applied the principle of construing insurance policies contra proferentem, meaning any ambiguity in the exclusion clause would be interpreted against the insurer.

The High Court allowed the appeal, finding that the insurer was liable to indemnify the Gibbs for the damage to their home.