Re: Building New on Burned out lot
It is good that you know the foundation is unstable and needs to be replaced. Heat kills cement.
As Ed said, the foundation must be placed on undisturbed ground, so you may have to go slightly deeper if your demolition contractor isn't careful. What are the odds that your new home will be the exact same footprint as the one that burned? Odds are, it will be different, so when you are collecting bids (or your general contractor is ) for the demolition and replacement of the footings, all this will be taken into account.
We can only give you rough ideas of what to expect, it will take local contractors, on site, to give you specific details of what needs to happen. Good luck, and please, report back with your progress.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!