Builders FirstSource Inc. is buying professional building materials supplier ProBuild for about $1.63 billion, helping to diversify its business and expand its geographic reach. Privately held ProBuild Holdings Inc. runs lumberyards, component facilities, millwork shops, gypsum yards and retail stores across 40 states. The Denver company's 2014 revenue was approximately $4.5 billion. Dallas-based Builders FirstSource is a supplier and maker of structural and related building products for new residential construction in the U.S. CEO Floyd Sherman will serve as CEO of the combined company. Builders FirstSource's board approved the deal.