_Examination and Conservation of Helal El-Beah Mosque, Dakahlia, Egypt

Helal El-Beah mosque in Egypt was built from many different materials as sandstone, bricks and marble. These building materials were in a bad condition due to many degradation factors, mainly ground water and salt weathering, so many deterioration phenomena were appeared as horizontal and vertical cracks, salts, loss of the Islamic decorations in the fa?ade and mihrab (Prayer niche), detachment of the plaster, biological colonization and featured dark of the stone surface. Prior to the conservation intervention, the building materials were characterized to identify their components. Scientific conservation treatment was carried out for the long-term conservation of the mosque. Conservation operations at the mosque included: repairing and roof insulation, wet and dry cleaning, joining of cracked parts and surface consolidating, replacement of the Portland cement plaster with lime plaster, re-cladding the lower part of the interior brick walls with sandstone tiles, replacement and completion of the stone blocks.