Section 28. Lien of certain judgments postponed

Upon the filing of the
  written instrument or instruments of approval under  section  twenty-six
  of  this  article,  the  lien  of  all  money  judgments and attachments
  affecting such real property, or the moneys due under  a  contract,  and
  all  claims  and  liens  acquired  in  any  proceedings  upon  any money
  judgment, shall be subordinate in like manner  and  to  like  extent  as
  provided  in said section for the subordination of mechanics' liens, and
  any attachment issued or money judgment recovered upon a  claim,  which,
  in whole or in part, was not for materials furnished, labor performed or
  moneys  advanced  for  the  improvement of such real property or for the
  public improvement, shall be subordinate to all mechanics' liens thereon
  and shall also be  subordinate  to  all  judgments  recovered  upon  and
  attachments  issued upon claims for materials furnished, labor performed
  or moneys advanced for the improvement of such real property.