C.A. White Inc., based in New Haven, Conn., has filed applications for two residential buildings on a 27-foot-wide block-thru lot at 21 West 17th Street and 16 West 18th Street, in the Flatiron District. The northern one would stand 13 stories tall and have 12 residential units, each averaging 1,863 square feet apiece. The southern one would be a 10-story, nine-unit structure with average residential units of 1,882 square feet, both indicative of condos. Morris Adjmi Architects is the applicant of record. Two- and three-story structures on the 18th and 17th Street ends, respectively, must first be demolished. Both addresses are in the Ladies Mile Historic District, which means the Landmarks Preservation Commission would have to approve both the demolitions and new construction.