review the lease

actually you should check the lease, if you have one.

normally the lease will set forth the landlord's obligations to repair and maintenance...roof shall be one of them.

however, landlord will also try to limit his liability by writing something in the lease like the landlord shall not be liable for any and all damages....resulting from landlord's failure to maintain the structure...and tenant shall not have any claim against landlord...stuff like that.

anyway, review ur lease first.