The order of the Board affirming, changing or modifying the requirements of the order of the Director shall be served and posted in the manner specified by Sections 65.05, 65.06 and 65.07. If the order of the Board requires the performance of any work, it shall specify the time within which the work required to be done must be commenced, which shall be not later than 60 days following the issuance of said order, and shall further specify a reasonable time within which the work shall be completed. The Director may extend the time for completion for good cause upon written request for such an extension.