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  • Overview
  • Specs
  • Coverage Rate
  • Application

Efflorescence Blocker Protects Concrete & Masonry | Floors & Walls

Efflorescence Blocker is a versatile product designed to block and prevent efflorescence and alkali from rising to the surface of a porous concrete or masonry substrate. Works well on both floors and walls. Ideal for applications where efflorescence is not preventable and is constantly being removed.

Typically used on floors where waterproofing membranes failed or were not installed or other horizontal and vertical applications where moisture penetration is unavoidable. The finish results in a natural appearance, with some substrates slightly darkening

Efflorescence Blocker comes in 1 gallon and 5 gallon pails.

 Where is Efflorescence Blocker Used?

  • Waterproof Membrane Failures
  • Water Repellent Sealers
  • Concrete Floors
  • Retaining Walls
  • Garden Stones and Pavers
  • Walkways
  • Sound Walls
  • High Alkali or Mineral Substrates
  • Horizontal / Vertical Concrete
  • Concrete Curing Aid

Why Efflorescence Blocker?

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


Solids Volume 44%
VOC 0 g/L
Active Content 100%
Material Type Acrylic Copolymer Emulsion
Coverage per Gallon 175 – 225 sq’/gallon
Packaging 1 gallon and 5 gallon
Mix Ratio ready-to-use
Shelf Life 2 years in unopened container
Color of Material Opal White
Odor Slight Odor
pH 8.0 to 9.0
Flash Point Non-Flammable
Weight Approximately 8.6 lbs/gallon
Surface Dry/recoat Approximately 1 hour
Full Chemical Cure 5 to 7 days
ASTM C666 2200 Cycles – no effect
ASTM C672 100 Cycles No Mass Loss, No Scaling
ASTM D2243 Do Not Freeze
ASTM G154, 2,500 hours No Loss in Repellency
ASTM C672/C672M No Scaling, 100 Cycles Treated Concrete
ASTM C309 Pass
ASTM C1315 Type 1, Class B
Wind Driven Raing ASTM E-514-86, 98.8% Lead Reduction
Water Pen Fed Spec SS-W-110C, 75% Min Req, 97.2% Leak Reduction Chloride Ion Intrusion
Salt Pounding NCHRP No. 244 Series IV -95% Reduction No. 244 Series II – 87% Reduction
Chloride Ion Absorption No. 244 Series II -87%
Water Absorption CMU ASTM C140-75 98.2% Effective
Water Vapor Transmission ASTM D-1653-71 100% Vapor Permeable
Water Repellency ASTM C67-87 98.2% Effective
Weathering ASTM G-53 3,500 Hours – Charge
Surface Burning ASTM E84 Flame Spread 0, Smoke Development 0

Coverage rates will vary depending on substrate porosity and texture.

CMU Precision Block 200-225
CMU Split Face 180-200
CMU Scored/Flute 150-180
CMU Lightweight 165-180
Clay Brick 250-300
Concrete (Dense Masonry) 275-300
Clay Block 175-200
EIFS 150-180
Concrete 250-300
Concrete Curing 300-400


Test Panel: Always apply material to a mock wall or test panel.  Test wall or actual surface area to determine acceptable color, surface porosity, application rates and methods before starting general application.

Surface Preparation: Before application, the surface should be clean and dry with no oils, dirt, debris, or minerals such as efflorescence, lime and calcium. These stains, along with others, will prevent proper penetration of Efflorescence Blocker to sufficiently seal for the warranty period. We recommend using our Restore’N’Prep product as a pre-treatment to clean masonry surfaces. Once clean, allow the surface to fully dry before sealing or applying a top-coat (See Restore-NPrep listing for details).

Vertical Surfaces: For vertical applications, do not allow the product to drip.

Horizontal Surfaces: For horizontal applications, do not allow the material to puddle up. Backroll any heavily pooling areas


1. Prepare surface by removing any current efflorescence using RainGuard Restore-NPrep. The surface must be prepped, clean, and dry before product is applied.

2. Allow the substrate to dry for 1-2 hours (depending on the weather) after cleaning.

3. Apply 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 cause the appearance of the coating to be hazy. Back roll any drips or pooling. DO NOT atomize.

Clean Up & Disposal: Clean up promptly with mild soap and water before product cures. Dispose of according to local, state and federal regulations.

PRODUCT STORAGE: The recommended storage temperature is approximately 22 °C (72 °F). Do not damage containers. Store in a dry place. Do not store for extended periods in direct sunlight. Protect containers from resin and moisture contamination


Use material in a well-ventilated area. Protect the work of other trades. Protect shrubbery and other plants with drop cloths. Protect automobiles and all other areas not to be coated from overspray. Remove overspray from any windows, automobiles, metal, etc. as soon as possible should it occur. To prevent permanent staining, clean spills or leaks in a timely manner. All surfaces to be coated should be clean of any dirt and grime, efflorescence, lime run, form oils and release agents, grease, mud, excess mortar, and mold and mildew, etc. All cracks should be pointed or caulked. All voids, beeholes, masonry surface defects and openings such as conduits, pipes, drains, door frames, vents, air conditioner openings, electrical openings, control joints, or any dissimilar materials should be repaired using urethane or other approved patching. Do not apply to surfaces if moisture content is greater than 25% as measured with an electronic moisture meter. Do not apply materials in climates where freezing temperatures have existed prior to application. Allow adequate time for surfaces to thaw. Establish that air, surface, and material temperatures are above 40°F (4.4°C) and at least 5°F above the dew point prior to painting. Do not apply at temperatures below 40°F when temperatures are expected to drop below 40°F within 48 hours of application. Do not apply if rain, snow, or lower temperatures are expected  within 48 hours. Do not apply if relative humidity is greater than 90%.

NOTICE TO BUYER: DISCLAIMER OF WARRANTIES AND LIMITATIONS ON OUR LIABILITY: We warrant that our products are manufactured to strict quality assurance specifications and that the information supplied by us is accurate to the best of our knowledge. Such information supplied about our products is not a representation or a warranty. It is supplied on the condition that you shall make your own tests to determine the suitability of our product for your particular purpose. Any use or application other than recommended herein is the sole responsibility of the user. Listed physical properties are typical and should not be construed as specifications. NO WARRANTY IS MADE, EXPRESSED OR IMPLIED, REGARDING SUCH OTHER INFORMATION, THE DATA ON WHICH IT IS BASED, OR THE RESULTS YOU WILL OBTAIN FROM ITS USE. N0 WARRANTY IS MADE, EXPRESSED OR IMPLIED, THAT OUR PRODUCT SHALL BE MERCHANTABLE OR THAT OUR PRODUCT SHALL BE FIT FOR ANY PARTICULAR PURPOSE. NO WARRANTY IS MADE THAT THE USE OF SUCH INFORMATION OR OUR PRODUCT WILL NOT INFRINGE UPON ANY PATENT. We shall have no liability for incidental or consequential damages, direct or indirect. Our liability is limited to the net selling price of our product or the replacement of our product, at our option. Acceptance of delivery of our product means that you have accepted the terms of this warranty whether or not purchase orders or other documents state terms that vary from this warranty. No representative is authorized to make any representation or warranty or assume any other liability on our behalf with any sale of our products. Our products contain chemicals that may CAUSE SERIOUS PHYSICAL INJURY. BEFORE USING, READ THE SAFETY DATA SHEET AND FOLLOW THE PRECAUTIONS TO PREVENT BODILY HARM.