How do we prepare an existing masonry surface for treatment with silane water repellents?
For normal dirt and grime, pressure-washing with or without a light-duty cleaning agent is typically sufficient. Mold or fungus should be removed with a sodium hypochlorite solution in addition to pressure-washing. Efflorescence and mineral deposits should be removed with a chemical cleaner specifically designed for that purpose, following the application instructions carefully, especially for neutralization and rinsing of the substrate.
