You bought a house and now the roof leaks Does the previous owner need to fix?
Unless you got a guarantee with the house or can show that
something was done to hide the problem and can prove that in court,
it is your problem. You have to prove the previous owner knew about
the leak and did something to hide it. They are supposed to
disclose things they know about, but only if you ask. He can say he
didn't know about it and you have to prove him wrong. Also, it may
just have started.