A wall is then developed throughout the brackets. Then the finished treads are bolted set up. These treads may be of metal or Wooden or Wooden clad steel. Cantilever measures have to be developed by a structural engineer, to ensure that they remain horizontal and rigid with use over time. https://staircaseinspirations.weebly.com/blog/the-rise-of-cantilever-staircases-in-contemporary-homes