In any district in which single-family dwellings are permitted, a single-family dwelling and customary accessory buildings may be erected on any single lot of record at the effective date of adoption or amendment of this Ordinance, notwithstanding limitations imposed by other provisions of this Ordinance. Such lot must be in separate ownership and not of contiguous frontage with other lots in the same ownership. This provision shall apply even though such lot fails to meet the requirements for area or width or both that are generally applicable in the district in which such lot is located. Variances of requirements listed in Chapter 1147 Supplementary District Regulations of this Ordinance, other than lot area or lot width, shall be obtained only through action of the Board of Zoning Appeals as provided in Chapter 1179.