Dr. Ziegert is co-owner of the firm Ziegert Roswag Seiler ¨C Architekten Ingenieure. As a trained bricklayer and civil engineer, he gained his doctorate at the Technical University of Berlin after several years of professional experience in the field of damage and renovation of historic solid earth constructions. Today, he specialises in the planning and assessment of earthen buildings in Germany and abroad. He is a publicly appointed and sworn expert for "Damage in clay buildings" by the Berlin Chamber of Industry and Commerce.