We have excavated around an existing exterior stone chimney (10' below ground level) in order to create a new foundation for the addition on to our house. The chimney is standing but the architect says he wants the mason to pour a concrete wall with rebar around the base. Our concern is we don't want the stone chimney to collapse on the mason. Any suggestions as to how to secure the chimney while mason builds new support wall? Thank you in advance. Mark Schultz