Efflorescence Blocker is a versatile product designed to block and prevent efflorescence and alkali from rising to the surface of a porous substrate. It is ideal for applications where efflorescence is not preventable and is constantly being maintained. It is typically used on floors where waterproofing membranes have failed or were not installed or other applications where moisture penetration is unavoidable. The finish results in a natural appearance, with some substrates slightly darkening. Please keep in mind, Efflorescence Blocker is a preventative ? if the surface already has efflorescence staining, it will need to be removed first. Ideal for use on Waterproof Membrane Failures, Water Repellent Sealers, Concrete Floors, Retaining Walls, Garden Stones and Pavers, Walkways, Sound Walls, High Alkali or Mineral Substrates, and more!