Any structure which will, under this title, become nonconforming but for which a building permit has been lawfully granted prior to it becoming nonconforming, may be completed in accordance with the approved plans, provided construction is started within sixty (60) days of the date it became nonconforming and continues to completion within one year. Such structure shall thereafter be a legally existing nonconforming structure. (Ord. 1198, 11-9-2009)