Any variance or special use permit shall expire one year after the date of the filing of the resolution with the Town Clerk unless the applicant shall, within one year, obtain a legal building permit and proceed with the construction; or obtain a certificate of occupancy when no legal building permit is required. The Board may, upon written request and for cause shown prior to the expiration of the initial one-year period, renew the variance or special use permit for a second one-year period. Said request for an extension need not be advertised.