Unsafe structures. Nonconforming buildings damaged by fire, wind and other causes as well as structures declared to be unsafe due to general dilapidation may be restored or rebuilt for the nonconforming use it was used for last. Unsafe structures cannot be restored or rebuilt in a use which is more nonconforming than the structure was prior to becoming unsafe. When the unsafe condition was caused by fire, wind, or any catastrophic causes, the permit must be applied for within six months from the date of fire, etc. Otherwise, the building permit need not be granted. Once a structure is damaged in any way described above in addition to the above rules, the owner shall build a one-hour fire wall and fire roof containing no windows or doors on neighboring property side.