A variance shall lapse and shall become void six (6) months following the date on which the variance becomes effective unless by condition of the variance a greater time is allowed, or unless prior to the expiration of six (6) months, a building permit is issued by the building official and construction is commenced and diligently pursued toward completion on a site which was the subject of the variance application. A variance may be renewed for an additional six (6) months, provided that prior to the expiration of six (6) months from the date when the variance originally became effective, an application for renewal of the variance is made to the board of zoning adjustment. The board may grant or deny an application for renewal of a variance. (Ord. 622, 9-2-1980)