Rendering of the Charleston County Detention Center expansion. County Council approved a plan to build a Detention Center expansion on November 20, 2007. The design-build contract was awarded to M.B. Kahn on December 12, 2007. Estimated project completion dates: February 2010 for new housing portion, and August 2010 for total completion of project. Size: approximately 323,000 square feet. Cost: $100.76 million dollars. Capacity: 2,033 inmates total (figure includes new and existing construction).