Section 11. Dwellings damaged or moved

1. If a multiple dwelling be damaged
  by  fire or other cause to the extent of two-thirds or more of its value
  at the time of such damage exclusive of the  value  of  the  foundation,
  such dwelling shall not be repaired or rebuilt except in conformity with
  the provisions of this chapter relative to dwellings erected after April
  eighteenth, nineteen hundred twenty-nine.
    2.  If  any non-fireproof stair in any multiple dwelling be damaged by
  fire or other cause to such extent that such stair or the  first  flight
  thereof  above  the entrance story is required to be rebuilt, such stair
  to the extent that it is required to be rebuilt shall  be  fire-retarded
  throughout.
    3.  If  any  dwelling  be moved from one lot to another, such dwelling
  shall thereupon be made to conform to all the provisions of this chapter
  relative to light, ventilation, fire protection and egress of a dwelling
  erected after April eighteenth, nineteen  hundred  twenty-nine,  but  no
  frame  building of any kind whatsoever shall be moved so as to be placed
  upon the same lot with any multiple dwelling,  nor  shall  any  multiple
  dwelling  be  moved  so as to be placed upon the same lot with any frame
  building.