Any lot of record existing at the effective date of this section (Ordinance 871A, passed December 13, 1965), in any R district may be used for the erection of a dwelling even though its area and width is less than the minimum requirements set forth herein. Front, rear and side yards for existing lots of record shall not be less than the established yard prevailing in the immediate area, but in no case shall side yards be less than five feet. Where two adjacent lots of record with less than the required area and width are held by one owner, the Board of Zoning Appeals may require that the two lots be combined and used for one main building. When three or more lots of record with less than the required area and width are held by one owner, the Board may require replatting to fewer lots to permit compliance with minimum yard requirements. (Ord. 871A. Passed 12-13-65.)