Need help locating a law stating a buyer can not sue the seller

[Fritz Adrienne]

I sold a house 3 years ago that I renovated.  The home inspector suggested that house could use a new roof, even though I had a roofing company provide a letter stating the roof has 10 more years of life expectancy (the roof overall was in pretty good shape).  The home inspector also recommended sealing valleys and flashing as routine maintenance in order to prevent leaks, which i did.  The buyer signed off on the disclosure that stated he would accept the home without a new roof.  3 months after the closing a small leak developed in the kitchen.  The buyer is now suing me for a brand new entire roof, and this case is even going to arbitration.  I found so many articles explaining why the buyer can not sue the seller, but can not find the exact law or statute stating this.  Does anyone know of a specific case (xxxxx vs yyyyy) that sets a precedence that buyers know of certain risks involved with purchasing a house (buyer beware).  The house is in Pennsylvania.  Thank you.