Thank you all for the feedback and suggestions. As he rebuilt most the piers I am a bit perplexed why the gap was not accounted for during the construction of the pier. Steel shims will work to provide a non-compressible shim but how best should he compensate for the gap between the top of the pier and steel shim (some gaps are greater than 2-3 inches). As this was part of a remodeling job, the interior walls and floors have all been finished and I'm worried that if he jacks again to make repairs to these spacers/shims (if he agrees to do so) that he will crack the work just completed. Is interior damage likely if it's jacked just enough to replace or modify the shims... Thanks for the advice, I'm struggling on how to resolve this.