$32 Million Office Building to be Largest in Clayton - Work will begin next spring on Carondelet Avenue in Clayton. The 19-story, 380,000-square-foot building called the 7700 Corporate Tower and is being developed by Nooney Co., a Clayton-based development and real estate management firm. The building will feature an aluminum and tinted-glass skin, with rounded corners on the exterior, will have 20,000 square feet per floor. It will have more floor space than most office buildings in the metropolitan area, Nooney said.