Mitten is proud to be part of the Cornerstone Building Brands family - North America’s #1 manufacturer of windows, vinyl siding and metal accessories. As a trusted leader of exterior building products, with an expansive national footprint, Cornerstone Building Brands is dedicated to efficiently and effectively meeting the needs of customers and communities.As a coast to coast distributor of premium exterior building products Mitten serves as the link between architects, builders and installers providing an endless variety of business and design solutions. Our Canadian made vinyl siding has ...