Being sued for not disclosing Rotten Boards under the roof

[Rashid Ghafoor]

I flipped a property over three years ago. I had hired a contractor to install a new roof before the sale. The roof was inspected and passed by a windstorm engineer.  Yesterday I received a letter from the buyer's attorney, threatening to sue me because the buyer supposedly started getting roof leaks at different locations of the house one year after purchase. According to the lawyer his client had someone look at the roof and they told him there were rotten boards under the flat roof. Supposedly the buyer contacted the roofer who installed the roof and asked him if he was aware of rotten boards. The contractor told him that he knew about the rotten boards and had informed me about them. But he said that I told him to install flat roof over the damaged boards anyway because it was cheaper. so the buyer is claiming that I knowingly did not disclose the rotten wooden boards. Therefore he is demanding $33000 for damages.  I was never informed by the roofer about any rotten boards and I was never aware of any rotten boards. I reached out to the roofer for explanation and he speaks very little English but says he never told the buyer any such thing. I am wondering does the buyer have a case against me after three years for non disclosure of something that I wasn't even aware of? What are my options if I get sued?