In any district in which single-family dwellings are permitted, notwithstanding limitations imposed by other provisions of this chapter, a single-family dwelling and customary accessory buildings may be erected on any single lot of record on July 1, 1988.

A two-family dwelling may be erected on a single lot of record on July 1, 1988, provided such lot is located in a district which permits two-family dwellings and further provided that at least 25% of all other lots fronting on the street upon which the lot fronts, between intersecting streets, are of lesser width and area than the average of all substandard lots fronting on the street in question between intersecting streets. Such lot shall be in 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 applicable in the district, provided that the yard dimensions and other requirements not involving area or width, or both, of 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 board of adjustment. Sale of nonconforming use is allowed if all provisions are met.