Within the framework of the multinational UNESCO-Program to safeguard the Old City of Sana’a the German side got involved for preservation of the 250 years old historic merchants building. A revitalization to a National Art Center for studies, ateliers, laboratories, and exhibitions was desired. In close cooperation with experts team of the GOPHCY the building was first to be documented with accurate drawings and its construction details and elements to be carefully investigated. Based on these results a detailed conception for the renewal and restoration of the historic monument was elaborated. One target of the cooperation and preservation program was the revitalization and promotion of a skill program for traditional Yemeni handicraft like masonry with mud mortar and bricks, natural wooden beam ceilings, decoration belts with patterns of bricks and plasterworks of gypsum, treatment of wooden shutters and doors and particularly the application of Qadath, the old techniques for roof covering and wet rooms.