Under ordinary circumstances, a contract is a contract. It binds the parties to the agreement. If, however, your contract allows you to walk away if the inspection is unsatisfactory, I would think you could do that and recover your earnest money. If, after the discovery of the problems, you entered into another agreement that indicated you would go through with the deal if certain remedies were put into place, you may have committed yourself -- particularly if the sellers have spent money to supposedly repaid the defects that you complained about.
I understand your hesitation now, particularly if you have asthma or similar conditions. I also do not understand how the seller can expect you to pay $5,000 for a "small roof". Seems to me that, if the roof needs repair or replacing in order to sell the place, it should be a seller cost.
You should confer with a good real estate lawyer in your area. For a modes fee, you can get the guidance you need in addressing this major issue.
Answered on May 14th, 2012 at 3:27 PM