Legal Liability Coverage for a Lessee?

We have an insured who has signed a lease that makes him responsible only for the roof. I interpret the damage to premises rented to you coverage under the CGL form to apply to this exposure if the insured is legally liable for the damage. But, the CGL form is a negligence contract, and if damage is caused by hail or an act of God, something for which the insured is not liable, the insured would have no coverage. Is this correct? Or does the damage to rented premises coverage apply no matter what the circumstances of the loss? Finally, would the legal liability coverage form be of use to the insured?

Indiana Subscriber