Section 264. Conversion of certain dwellings

1. Notwithstanding any
  inconsistent provision of this chapter or of any other law, it shall  be
  lawful  until  July first, nineteen hundred forty-nine, for any owner to
  convert a non-fireproof dwelling which is not of frame construction, not
  more than a basement and two  additional  stories  in  height,  and  not
  occupied by more than two families, for occupancy by not more than three
  families,  in  accordance with the provisions of this section, providing
  such dwelling was existing on April eighth, nineteen hundred  forty-six,
  or  was erected thereafter under plans on file with the department on or
  before such date.
    2. The provisions of article six of this chapter shall  not  apply  to
  conversion  of  dwellings  under  this  section,  except  in  so  far as
  compliance therewith is expressly required as provided in or pursuant to
  this section.
    3. Conversion of such dwellings under this section must be made:
    a. In full compliance with the  provisions  of  sections  one  hundred
  seventy-six, one hundred seventy-seven, and one hundred eighty-eight, of
  subdivision  two  of section one hundred eighty-nine, and of section two
  hundred;
    b. In full compliance with  the  provisions  of  section  one  hundred
  eighty-five,  except  that  if a cellar ceiling is plastered and in good
  repair only the area of the ceiling  over  any  boiler  located  in  the
  cellar  and  for  three  feet beyond need be covered with fire-retarding
  material;
    c. In full compliance with  the  provisions  of  section  one  hundred
  eighty-seven  unless  such  conversion  was completed under authority of
  this section before July first, nineteen hundred forty-seven, and
    d. In compliance with such additional provisions  of  article  six  of
  this  chapter,  and no other, as may be specifically required by, and in
  accordance with, rules and  regulations  of  the  department  where  the
  conversion is proposed to be made.
    4.  A  plan  of  alteration  to effect conversion of any such dwelling
  under this section  shall  be  filed  with  such  department  and,  when
  approved  by  it,  shall  constitute  a  lawful  plan  for  three family
  occupancy of such dwelling.
    * NB Expired July 1, 1949