All permits issued under this chapter shall expire by limitation six months after the date of issuance, if the work authorized by the permit has not been commenced. If, after commencement, the work is discontinued for a period of 12 months, the permit therefor shall immediately expire. No work authorized by any permit which has expired shall thereafter be performed, until a new permit therefor has been secured.
(G.S. § 160A-418) (1992 Code, § 150.24) Penalty, see § 150.99