N.Y. General City Law § 62

§ 62. Key space. All ceilings, stud partitions and furred walls in\ntenements, apartments, hospitals, schools, and other public buildings\nwhere plastered with lime on wood lath shall have not less than\nthree-eighths space between lath. All grounds and jambs shall mean not\nless than seven-eighths from the stud.\n