OSR is a national commercial and industrial roofing provider headquartered in Chicago, IL. Established in 1987, OSR ranks among the Top 20 Roofing Contractors in the country (Top 10 among exclusively commercial roofing companies) and is registered and licensed in 48 states. As one of the fastest-growing commercial roofing companies, our growth has been driven largely by recurring business from numerous respected general contractors, architects, engineers, and building owners nationwide.