It is not intended by this chapter to repeal, abrogate, annul or in any way impair, or interfere with existing provisions of law, ordinance, or with any rules, regulations or premises, unless specifically repealed by this chapter, or with any private restrictions placed upon property by covenant or deed; provided, however, that where this chapter imposes a greater restriction upon the use of buildings or premises, or upon the height of buildings, or lot coverage, or requires greater lot areas or larger yards, courts or other open spaces than are imposed or required by existing provisions of law, or ordinance or by such rules, regulations or permits or by such private restrictions, the provisions of this chapter shall control.