Mid-States Concrete Products manufactures flexicore prestressed concrete slabs, precast concrete beams and columns and other precast concrete building materials. Mid-States Concrete Products supplies contractors and developers throughout Wisconsin, northern Illinois, eastern Iowa and Michigan s upper peninsula. Flexicore floor and roof slabs were first produced in 1938 by the Illinois-Wisconsin Concrete Pipe Company at a time when Mid-States founder, Charles Harker, worked for the company and supervised the flexicore operation. Nearly 10 years later, after the company discontinued the operation, Harker founded Mid-States, which received regional attention for its first major project where it provided flexicore for a 150-unit University of Wisconsin faculty housing project. Today, the company continues to produce flexicore hollow core slabs and flexicast beams and columns. Headquartered in Beloit, Wis., Mid-States Concrete Products employs more than 100 people.