Like other siding types, traditional stucco can collect grime and be vulnerable to algae and mold over time. Before cleaning stucco, inspect it for damage or cracks. Water that gets inside cracks or openings can lead to deterioration, including mold growth.
If you don’t find any damaged areas, move ahead with cleaning. Use a medium bristle brush to remove algae, grime and mold from the surface, then rinse the area. Use a garden hose to rinse, as high-pressure water can damage the stucco.