Tom's advise is right on, the only thing I might be able to add, and I do so with reservations, is that it is possible, if you live in the right city, that the city inspectors might be willing to review the property. It might seem like a circumvent, but it is not. I would discuss the issues with them prior to spending one dollar and find out there position, if offered.
It has worked for me in the past, but they are very tentative if it is a major bad issue, and rightfully so. If the city won't offer you any suggestion, or can't, I would follow advise you find that engineer.
Remember that once you involve them [city authorities], if the problem is serious, they can mandate that it be resolved, ergo another reason I have reservations, but profer this advice.