Section 211. Height and bulk

1. No tenement shall be increased in height so
  that  its  height  shall  exceed  by more than one-half the width of the
  widest street upon which it stands.  Except  as  otherwise  provided  in
  subdivision  four  of  this  section, no non-fireproof tenement shall be
  increased in height so that it shall exceed five  stories,  except  that
  any  tenement  may  be  increased  to  any height permitted for multiple
  dwellings erected after April eighteenth, nineteen hundred  twenty-nine,
  if  such  tenement  conforms to the provisions of this chapter governing
  like multiple dwellings erected after such date.
    2. If there are bulkheads, superstructures or penthouses exceeding ten
  feet in height or exceeding in aggregate area ten per centum of the area
  of the roof, the measurement of height shall be taken to the top of such
  bulkhead, superstructure or penthouse, except that this shall not  apply
  to  elevator  enclosures  not exceeding twenty-three feet in height used
  solely for elevator purposes, nor  to  open  pergolas  or  similar  open
  ornamental treatment of roof-gardens or playgrounds.
    3.  In  a  fireproof  tenement  house  in  which one or more passenger
  elevators are operated, penthouses may be  erected  on  the  main  roof.
  Such  penthouses  shall  be  set  back at least five feet from the front
  walls and ten feet from the rear walls of  the  dwelling  and  at  least
  three  feet  from  any  court  wall.  Such penthouses shall have a clear
  inside height of not less than nine feet from finished floor to finished
  ceiling, and shall not exceed twelve feet in height from the high  point
  of  the  main  roof  to  the  highest point of the penthouse roof.  Such
  penthouses shall not be deemed to affect the measurement  of  height  of
  the  dwelling.  All  such  penthouses shall be entirely fireproof except
  that windows shall not be required to be glazed with wire glass.
    4. Any non-fireproof old-law tenement five stories in  height  may  be
  increased  in  number  of  stories to six provided that such increase in
  number of stories does not result in an increase in the  height  of  the
  roof  beams  above the curb level. In any tenement so altered, the first
  floor above the lowest cellar, or, if there  be  no  cellar,  above  the
  basement or other lowest story, shall be fireproof. Any yard or court of
  such  altered  tenement  shall  not  be  less  in any dimension than the
  minimum dimensions prescribed in section twenty-six.