All grading and excavation in or contiguous to residential neighborhoods shall be carried on between the hours of seven a.m. to five-thirty p.m. The zoning administrator may waive this requirement if it is shown that restricting the hours of operation would unduly interfere with the development of the property and it is shown that other properties or neighborhood values would not be adversely affected. (Ord. 111 §1, amended, 1985; Prior code §12-107-6(F)(2))