The answer to this question may surprise you. Even if your roof is not damaged by an accidental external cause and just becomes old and worn out which allows rain water to leak inside causing water damage to your walls, ceilings, carpet, etc.; that damage IS a covered loss under the typical Homeowners (HO-3), Apartment and Commercial building (Special form) policy subject to your deductible.
But, what about the “wear and tear” exclusion? You’re right, “Wear and Tear” is a main exclusion in your Homeowners and other property policies and that exclusion in this example applies to the roof itself. A worn out roof will NOT be covered because it must first be damaged by “accidental direct physical loss”. If the roof is damaged by a wind storm, hurricane or tornado or some other accidental cause then the roof itself would be a covered loss.
The reason that the resulting water damage to the rest of your home or building is a covered loss is because the “wear and tear” exclusion goes on to say, “However, we do insure for any resulting loss.” This makes sense when you consider that most other covered water losses result from something that failed because of wear and tear and leaked water causing damage – like a water pipe that rusts and leaks, or a hot water heater that wears out and leaks, or a water connection that gets old, splits and leaks. So, this is why insurance companies monitor and care about the condition of your roof.
NOTE: Because of this exception to the “wear and tear” exclusion insurance companies may periodically inspect the roof on property they insure to make sure it has not worn out. If a roof becomes deteriorated or neglected, the insurance company may insist that the roof be replaced or they will refuse to stay on the risk and cancel the insurance policy.
For answers to other related questions click: WATER DAMAGE ~ Am I Covered?