LandAmerica Financial Group Inc., a premier provider of real estate transaction services, acquired the assets of National Assessment Corp., a full-service real estate due-diligence firm specializing in engineering, construction and environmental assessments associated with commercial real estate acquisition, finance and surveillance. Headquartered in Alameda, CA National Assessment Corp., utilizing a network of over 300 professional associates, provides environmental site and property condition assessments and real estate loan services throughout the country. It will operate as a part of LandAmerica’s National Commercial Services group.