Storm, rainwater and a short circuit

Rule. Proximate cause is the dominant, effective cause of the loss - the one that sets the chain in motion, not necessarily the last event in time (Leyland Shipping v Norwich Union). Where a new and independent cause intervenes, the later cause may displace the earlier one.

Apply element by element.

1. The stripped slates. Proximate cause is the gale: storm damage, covered. The age of the roof goes to condition and betterment, not to causation.
2. Rainwater staining to ceiling and stock over three days. The rain is not a separate peril here; it is the mechanism by which the storm caused damage. The proximate cause remains the storm, so this is a storm loss, not an escape-of-water loss (which requires water escaping from a defined installation, not the sky).
3. The fire in the storeroom. The short circuit is a new and independent cause, and the fire is the proximate cause of the fire damage. It does not matter that the storm let the water in; the fire is a covered peril and is not 'caused by' the excluded perils.
4. Firefighting water damage. Damage caused by reasonable steps to extinguish the fire is treated as part of the fire loss. Covered.

Conclusion. The storm and fire elements are covered; the wear and tear exclusion bites only on the roof itself, not on the consequential damage it let through. The insurer should not use wear and tear as a blanket declinature.

Rule. An exclusion applies only where the excluded cause is the proximate cause. Concurrent causes are resolved in the insured's favour where one insured peril is a genuine effective cause. Wear and tear excludes the cost of putting right the deteriorated item itself; it does not automatically exclude damage caused by a separate insured event. Faulty workmanship must itself be a proximate cause.

Apply. The deteriorated slates made the building vulnerable, but a gale that strips slates is the effective cause of the loss; without the wind there would have been no loss that day. Vulnerability is not causation. Repointing the ridge is a separate, unconnected item and the fire had nothing to do with it. Betterment still applies: the insured gets new slates for old, so the insurer may deduct the improvement in value (or apply new-for-old depreciation) on the roofing element, and may make a deduction for the pre-existing wear and tear on the roof covering itself.

Conclusion. Pay the storm element less a wear-and-tear/betterment deduction on the roof covering; pay the fire element and the firefighting water damage in full; apply average if the sums insured are inadequate. If the insurer wants to rely on faulty workmanship, it must show that the repointing, not the wind, caused the ingress.

Not by itself. The general rule is that an insured is not obliged to insure; the duty is to take reasonable steps to avert or minimise loss once it is known, and to act honestly. A failure to notice damage is not a breach of a condition unless the policy imposes a specific obligation, such as keeping the premises in good repair or inspecting after severe weather.

Application. Three days' unnoticed ingress in a closed storeroom is not obviously unreasonable. A claim condition requiring notification 'as soon as practicable' would be construed with reference to what a reasonable insured could do, and the insurer must show prejudice before declining for late notice. If, however, the policy contains a specific condition requiring inspection and reporting after storms, or a risk-improvement requirement following the surveyor's recommendation, the insurer's position improves considerably - the failure to re-slate after an 18-month-old written recommendation is much stronger evidence than the three-day delay.