回複：Thank you very much for your very useful advice but I st

I am living in Texas where may be different from your state.

In Texas, a builder will buy an insurance for major structures like foundation. The insurance is valid for 10 years. Home owners buy home insurances which do not cover foundation.

My advice is:
1. hire an foundation engineer to evaluate how serious the problem.
2. If it is serious, you need to figure out whether you can prove that the previous owner did know that there is the foundation problem.
3. If you cannot prove that, you may just do something and sell the house. You do not want to leave any records that you do know that there is foundation problem. So you do not have to disclose it when you sell the house.
4. Otherwise, in case you have to file lawsuit, just be very patient. It will be very frustrating.