"settling" building investment property
i was looking at two potential investment properties and both had floors that had slopes - they were not level. both of the agents said that the buildings (one a condo built in 1929 and one a house built in 1900) "settled" or were "settling." one of the agents told me i could repair it by tearing up the floor and installing a new sub-floor. is "settling" something i should just walk away from? is installing a new sub-floor a solution? and if it is, how big a job is that? thank you for any insights and advice anyone can give