In any zoning district in which single family dwellings are a permitted use, notwith-standing the regulations imposed by any other provisions of this Article, a single family dwelling may be erected, and thereafter maintained, repaired, restored, replaced, altered, and enlarged, on a legal nonconforming lot of record that has a width and area each equal to at least 80 percent of the lot width and area required in the district in which such lot is located, provided that such construction shall comply with all the regulations (except lot area, shape, width, and depth) applicable to single family dwellings in such zoning district.