A. In any district 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 Part 1, notwithstanding limitations imposed by other provisions of this Part 1. Such lot must be in single and separate ownership and not of continuous 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, provided that yard dimensions and requirements other than these applying to area or width, or both, of the lot shall conform to the regulations for the district in which such lot is located. Variance of yard requirements shall be obtained only through action of the Zoning Hearing Board.

B. If two or more lots or combinations of lots and portions of lots with continuous frontage in single and separate ownership are of record at the time of passage or amendment of this Part 1, and if all or part of the lots do not meet the requirements established for lot width and area, the lands involved shall be considered to be an undivided parcel for the purposes of this Part 1, and no portion of said parcel shall be used or sold in a manner which diminishes compliance with lot width and area requirements established by this Part 1, nor shall any division of any parcel be made which creates a lot with width or area below the requirements stated in this Part 1.