[M-IS05] Geomaterials in cultural heritage: weathering, investigation techniques, and conservation

[MIS05-P02] Salt weathering of a historic building in Budapest, the role of soluble salts and moisture

*Akos Torok¹, Annamária Kis¹ (1.Department of Engineering Geology and Geotecnics, Budapest University of Technology and Economics)

Keywords:salt, brick, moisture content, diagnostics, weathering

A historic building located in the city centre of Budapest, Hungary, displays various salt attacks. The study focuses on detecting salts and tracking salt decay patterns using on-site diagnostic tools and laboratory tests. The building that formerly hosted a ballet school was constructed between 1883-1886 in a Neo-renaissance style. Its 4-storey facade displays various construction materials, including stone, brick and painted renders. The building is under restoration, but newly developed salt efflorescences cause significant problems regarding aesthetics and structural integrity. The salt weathering problem was addressed using on-site diagnostic tools and a sampling campaign for laboratory tests. The on-site tests included moisture content detection and salt mapping. Core samples were drilled to understand the construction material layers of the structure and to obtain samples for laboratory tests, focusing on mechanical properties and mineralogical composition. Dry drillings were also made perpendicular to the surface, and drilled powder was collected to detect moisture content and in-depth composition of the facade. Our study has proved that salt deterioration is linked to improper sealing of the roof and infiltration of the precipitation water into the porous limestone ledge and the brick and render of the building.