Waste minimization and worker protection at D&D sites requires continual and extensive characterization for radioactive contamination. Contamination detectors that are sensitive, rugged, fast, and capable of covering large areas are needed. The concrete surface monitor (CSM) developed at LANL supports both characterization and waste minimization efforts at D&D sites containing large concrete surfaces and structures of different forms and shapes. This report describes the CSM design and the results of several field experiments