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  • Efflorescence Blocker ®

    • Prevents Mineral and Alkali Staining
    •  Excellent Scratch and Stain resistance
    •  Resists Hot-Tire Pickup 
    •  Prevents costly construction repairs

    Please Note: Current efflorescence staining will need to be removed first. Please see Restore-N-Prep.

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    EFFLORESCENCE BLOCKER® Material Warranty
    5 Yr Warranty Apply 1 Coat

    Product Overview  |  Technical Data
    Coverage Rates
      |  Application Guidelines

    1 Gal RTU


    5 Gal RTU


    Technical Documents




    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.


    • Blocks efflorescence and alkali from coming to the surface
    • Ideal for planters and groundwater penetration
    • Resists hot-tire pickup
    • Excellent exterior durability
    • Direct and reverse impact resistant
    • Works as a universal primer
    • Water and stain-resistant
    • Wet and dry adhesion

    Recommended Uses

    • Waterproof Membrane Failures
    • Water Repellent Sealers
    • Concrete Floors
    • Retaining Walls
    • Garden Stones and Pavers
    • Walkways
    • Sound Walls
    • High Alkali or Mineral Substrates
    • and more!

    Coverage Rates (Theoretical)

    Substrate Sq Ft / Gallon # of Coats*
    CMU (Precision Block) 200-225 1
    CMU (Split Face) 180-200 1
    CMU (Scored/Fluted) 150-180 1
    CMU (Lightweight) 165-180 1
    Clay Brick 250-300 1
    Stucco 225-275 1
    Dense Masonry Surfaces 275-300 1
    Clay Block 175-200 1
    EIFS 150-180 1
    Concrete 250-300 1
    Concrete Curing Aid** 300-400 1

    *Always apply material at the appropriate spread rates. Please see Technical Data Sheet for correct application instructions.

    **See TDS for details.

    How To Use

    1. Remove any current efflorescence using RainGuard Restore-N-Prep.
    2. Allow the substrate to dry for 1-2 hours depending on the weather.
    3. Using a synthetic 3/4″ nap roller, a hand pump sprayer, or airless sprayer, apply Efflorescence Blocker in a thin coat by using just enough material to wet the substrate. DO NOT apply in a flood coat. Applying too much material may turn the appearance of the coating hazy. Backroll any drips or pooling as soon as possible. Do not atomize. Efflorescence Blocker needs to saturate the substrate so it penetrates and blocks the pores without creating a film.
    4. Allow to dry for at least 1 hour. Cure time is 5-7 days.


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    >> Find instructional videos of RainguardPro products on YouTube

    Restore and Protect with Efflorescence Blocker and Efflorescence Cleaner Learn More
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