CTA Exteriors & CTA Roofing: two unique business sectors, all under one roof. While commercial business owners & homeowners may have different project requirements, they share the same basic need — to be treated fairly & personally. And it takes a unique business to be able to serve both. CTA Roofing specializes in commercial and flat roofing, while CTA Exteriors is the residential, steep slope, & exterior expert. Both businesses are operated by the same leadership and offer personable teams with decades of industry experience .