I may be buying an old victorian house that has a riverrock foundation, unfortunately I live in california and we are prone to earthquakes. I somewhat understand the basics of retrofiting a new concrete foundation to the existing river rock foundation, but I do not understand all of it. I know how to frame and pour the concrete next to the river rock, but how do I attach the new foundation to the old? Bolts? rebar? Are there any tips or websites I should look up?