No building or other permits or approvals in connection therewith shall be issued by the Building Commissioner or other City officer or employee for any structure, appurtenance or use on a lot in a subdivision for which a plat has not been approved and recorded as provided for in these Subdivision Regulations, nor shall any such permit or approval be issued on any lot in any subdivision even if properly recorded, until after the required paving and underground improvements have been installed by the allotter and certified ready for use by the City Engineer.
   Nothing contained in this section shall bar the issuance of permits and approvals for additions or modifications to existing buildings or for construction that has been started prior to the effective date of these Subdivision Regulations (Ordinance 21-1965, passed July 13, 1965). (Ord. 21-1965. Passed 7-13-65.)