Once you have all these contacts come-up with a concrete mix, let me see it if you would like my opinion.  I will let you know if I agree or disagree & possible improvements. IMPORTANT: Is this an existing room?  Is this room "on-grade"?  Do not forget concrete weighs 150F#/cubic foot  ///  5,300 pounds per cubic meter.  Nothing better than collapsing your house. Best to you,zz. |  
  |