Knox's Construction provides new roof installations, roof repairs, siding, and gutter & downspout products and services Knox is your trusted roof repair and property renovation solution for your home, since 2002. Need the best roofing available in Canonsburg, PA, and surrounding communities? We install roofing and repair roofing throughout Washington and Allegheny Counties in Pennsylvania. We offer expert roof workmanship, quality, and customer service. Call (724) 941-8219 for a free estimate.