I hesisate to suggest seeing a lawer, but this didnt go bad overnite.
Was there ANY indication of a earlier problem / fix and more important
was this area disdclosed before sale to have troubles?

If they knew and covered it up the old wwners are on the hook for $$
repair cost!

I sold a home just over a year ago and discllosed everything, so they
couldnt come back and get me for repairs