John Sonnentag graduated from UW-Eau Claire in 1966 with degrees in business administration and history. Carolyn Sonnentag graduated from UW-Eau Claire in 1967 with a degree in medical technology. After graduating from UW-Eau Claire, John joined the family business, which at the time was named County Concrete Corp. Carolyn later joined the business and worked as a bookkeeper in the finance office. John’s father, Merlin, founded Sonnentag Concrete and Gravel in Marathon in 1946. The company offered concrete block and aggregate in the first two decades, but under John’s leadership, the company expanded its product line and began offering concrete pipe and other precast products. The company was renamed County Materials Corp. in 2003, and though it is still headquartered in Marathon County, the company now has additional locations in Wisconsin, Illinois, Iowa, Indiana, Missouri and Florida.