The details of the scope of work and the details of the contract of what is considered a hidden defect or to be dealt with as a change order of the other contractor would have told you this.

The property would have been condemned without the defect cured.

They didn't want to bother me, so they never said anything.Anyway, a couple of months ago 1 of the guys collapsed with a heart defect and supposedly during some examinations they said he had a little mold in his lungs.

They buy "scratch and dent" loans which means that the loans have fraud or other defects in them and so they have taken on the liabilities of those loans as well.

If there is a defect in the loan it may not sell at all.  

Ok, so let's address some possibilities one by one to see what is likely.If you found out that there are material defects in the property (which you have) then it is entirely appropriate to ask for some form of "fix" if strategically it makes sense to do so.It is possible that the agent is reluctant to include your request for a price reduction commensurate with the level of damage to the property for a variety of reasons.  

When you sell, you are required to disclose all known defects.

@Tim Sutton - I think a lot of the numbers look very solid, if there are no major defects in the building such as weird layouts, or missing elements, then your next step should be to get a close inspection of the plumbing to make sure you won't be replacing all the pipes in 5 years, check the electrical to ensure you have good electrical panels and modern wiring, get a timeline on the life of the roof, and make sure the foundation gets a good look.If these major ticket items are fine, then I would say to get this one under contract and start moving forwards.

Originally posted by @Sarah Shockley: but since you already closed on the property, that constitutes you accepting the property in that condition and accepting their omission of that information.Not if the omission was misrepresentation or failure to disclose a material defect known to the seller.

Somebody wanting to sue for you backing out of a bad deal or accusing you of selling them a property with defects like unknown termite damage).