It is not intended by this chapter to repeal, abrogate, annul or in any way to impair or interfere with existing provisions of other chapters or ordinances, except those specifically repealed by this chapter, or with private restrictions placed upon property by deed, covenant or other agreements. However, where this chapter imposes a greater restriction upon land, buildings or structures than that imposed by existing provisions of chapters, contract or deed, the provisions of this chapter shall control. Where the provisions of this chapter are, or become, repugnant to state or federal law and such differences cannot be reconciled therewith, the provisions of such law shall govern.