Restoration. Any nonconforming structure partially damaged by fire, casualty or act of God may be repaired, restored, reconstructed or used as before, provided that the area of such use, building or structure shall not exceed the area which existed prior to such damage. All repairs shall be completed within one year after damage occurs or such use shall not be rebuilt except as a conforming use. In the event substantial damage occurs, then the provisions of § 410-47B shall apply.