Great Lakes Systems, also known as GLS, is a roofing contracting company that installs a range of single ply roofing systems. Founded in 1969, it is an approved applicator for Firestone Industrial Products, Sarnafil, Duro-Last Roofing and Haartz-Mason. The company has a fleet of trucks, conveyors, hydrocranes and power gravel movers. Great Lakes Systems also conducts outside and in-house training programs for personnel. It operates service and sheet metal departments. The company s clients include SDH Construction Services, P&K Steel Service, Forest Hills Public Schools and Barnes Management. Great Lakes Systems has undertaken several projects, including Spectrum Hospital, Kent Hills Elementary School, Hamilton Middle School and the Zollar Student Activity Center. It is a member of the Midwest Roofing Contractors Association, National Federation of Independent Business, National Roofing Contractors Association, and Associated Builders and Contractors.