A permit issued under this building code from the date of issue shall be void after six months if the work contemplated under the permit is not begun within that time or if such work does not proceed at a reasonable rate towards completion. However, an extension may be granted if applied for prior to the expiration of such six-month period at the discretion of the chief code enforcement officer. When construction work has been stopped for a period of six months or longer, then the building permit issued for that construction shall be void and a new building permit must be issued before the work is resumed. Construction started but not completed and on which a building permit has expired and on which a new permit is not granted, shall be subject to condemnation. (Prior code § 5-14)