Your experience with foundation issues?

[Ashley Benning]

I'm looking at an REO property that is a pretty cosmetic flip except for one thing: HUGE cracks in all the cement under the flooring. Apparently this is common in this area as the builder was a crook and did not put rebar in the foundations when the houses were built in the 1960s. I'm going to bring in a specialist to quote the repair work, but before I do that I'd be interested to hear some worst-case scenarios you have experienced. Am I looking at a $20,000 job, or a $100,000 job? Single level slab foundation, 1300 sq ft house