Over the last decades air pollutants caused severe damages. Under supervision of the Norddeutsches Zentrum für Materialkunde von Kulturgut e.V. ZMK, scientists and restorers searched for methods helping to preserve the precious stones for the posterity.

According to extensive damage analyses and a series of laboratory tests, ORMOCER®G, a product developed by the Fraunhofer Institute for Silicate Research, was used for the first time in this project. Among others, ORMOCER®G is aimed at the replenishment of glazes. Different decorative elements of the church portals of St. Jakobi’s as well as of a Lüneburg patrician house from the Renaissance were successfully treated with ORMOCER®G. At two more churches in Mecklenburg-Western Pomerania, comparative surveys were carried out.

The uppermost principle for restoration was maximum preservation of the glazed and unglazed bricks and simultaneously minimal interventions. Only in individual cases polluted stones were replaced. Whether and how the restoration measure proves its worth will be shown in a long time observation of the church portals of St. Jakobi’s under supervision of the Brandenburg monument protection authority.