EX-2.1 2 d444643dex21.htm EX-2.1 EXECUTION VERSION STOCK PURCHASE AGREEMENT BY AND AMONG BEACON ROOFING SUPPLY, INC. (as Buyer) OLDCASTLE, INC. (as Parent) AND OLDCASTLE DISTRIBUTION, INC. (as Seller) DATED AS OF August 24, 2017 PAGE Exhibit A: Form...