Claim about cracking in a garage rejected due to questions about the definition of 'sudden'

What happened

Reggie discovered cracking to his garage. Concerned it might be subsidence, he contact his insurer. Their surveyor inspected the damage and agreed the building had moved. But rather than it be subsidence, they thought the cause was a lack of support to the rear wall. 

Reggie also took advice from an engineer who agreed with the insurer. 

Reggie thought he could claim under accidental damage after checking his policy documents. To him, an accident is something which happens by chance and without deliberate cause. This described the situation well to Reggie. 

But the insurer said the policy defined an accident to mean 'unforeseen physical damage caused suddenly'. They didn't agree the damage happened suddenly, so declined the claim. 

But when Reggie had been in the garage a week earlier, there was no sign of cracking. So he felt the cracking was sudden. 

What we said

We checked the policy documents and agreed with the insurer that it could rely on its own definition. 

We looked at reports from the insurer and Reggie's engineer. Both indicated that the lack of support caused the garage to move gradually over many months or years. 

The damage was clearly physical and we had no reason to think Reggie could have foreseen it. We acknowledged that the cracking may have appeared suddenly. But the policy definition referred to damage caused suddenly - not which happened suddenly. 

We thought the cause of the cracking was the gradual building movement. We were satisfied it wasn't accidental damage, as defined in the policy, so we decided that the insurer could fairly decline the claim. 

We may have come to a different decision if the definition of accidental damage had been different. For example, if the policy had referred to the damage being sudden rather than being caused suddenly.