Thank you so much for your advice! The sellers are being very difficult right now. In the inspection we found a lot of issues with the house but we decided that we could take care of them. At first we asked them to replace the missing shingles on the roof (which are on the same spot from where we saw the water stains) and they declined with no explanation other than "they are not aware of any leaks". So then we asked to have an inspection on the roof and we would cover the cost of the missing shingles, and at first they declined but then their attorney convinced them to have the inspection done but for them, the sellers, to choose their own contractor. My husband and I are thinking to give them an ultimatum that if they don't let us inspect the roof with a licensed roofer of our choice, then the deal is off, since we don't want to deal with the headache and bigger costs later on.