If you bought a foreclosure - you most likely agreed to purchase it "As-is". You also most likely signed an addendum to your contract that released the bank for all claims, and that stated they make no representations about the condition, or issues with the property. Additionally, I doubt there were any disclosures made by the bank that you could use to prove they were aware of any defects. Any action against the bank you purchased it from is probably futile at this point, and would be very hard to prove on your part.
FHA should have done their own inspection prior to approving your loan - did they find anything that was of concern then? Although unfortunate, this issue may have arose just within the last two years. I would suggest contracting a contractor/structrual engineer to take a look and offer suggestions for remedy.