Considering a purchase. Question about structural warranty

[Kevin Yun]

There is a property I am considering to purchase, (built in late 1800s), and after visiting the property today, the 3-flat house was visibly a little wavy (caved in / settled) on one side. (Imagine a deck of cards, bent a little).

Has anyone had experience with a structural warranty as a buyer? Or any advice you could provide?

Everything else seems to be pretty good for this property, and the structural point may be my biggest concern.