§ 8113-6.2.1. Whenever any such structure is voluntarily or involuntarily removed, damaged or destroyed to the extent of 50 percent or less of its floor or roof area before destruction, the structure may be restored to its original state existing before such removal, damage or destruction. The occupancy or use of the structure or part thereof which existed at the time of the partial destruction may be continued if the restoration is started within a period of 12 months after the occurrence of the partial destruction and is diligently pursued to completion. The 50 percent standard is a cumulative figure for voluntary removal. Successive alterations to the same structure that exceed a cumulative 50 percent cannot be made.