I totally agree ajw, I was brain storming the idea the builder would refuse to tear out and start over. And if the inspector looked at it and said the shell was too thin that could help. I believe the thickness is on the rebar sheet. Also the analysis of the gunite would be on the home owner if the PB or gunite company refused to have it done. This is all directed as suggestions to assist in turning a PB/ sub contractor who is not taking any responsibility.