Authorization granted by the city to construct a building or structure, or to change the use of land, shall not be denied or abridged in the event that construction has taken place thereon to the extent of one thousand dollars ($1,000.00) or more in replaceable value by the effective date hereof; provided, however, that such authorization to construct a building or structure shall be denied if construction would not have complied with all applicable laws and ordinances existing prior to the date of the ordinance amendment. "Replaceable value" shall be construed to mean the expenditure necessary to duplicate the material and labor at market prices. (Ord. 6-20-78A, 6-20-1978)