Rock-Block 3K

Available Sizes
  • 1.5 Gallon BAG-PAKTM Unit in a single pail
  • 3 Gallon BAG-PAKTM Unit in a single pail
  • 100% solids
  • Cost effective
  • Excellent adhesion
  • 0 VOC, no solvent odor
  • Five Year Warranty available
  • Easy working, medium viscosity formula
  • Independently lab tested and certified by CTL to achieve stated CLASS 1 PERM Rating when used as directed


ROCK-BLOCK 3K Moisture Barrier is a 100% solids, three-component, high performance clear penetrating epoxy sealer and primer that is uniquely formulated to effectively reduce moisture vapor emission rates (MVER) through a concrete slab to levels that allow subsequent installation of non-permeable floor finishes. When properly applied to the top side of a concrete slab per ROCK TRED specifications, ROCK-BLOCK 3K Moisture Barrier achieves a CLASS I VAPOR RETARDER rating of 0.1 PERM OR LESS per ASTM F3010-13. ROCK-BLOCK 3K Moisture Barrier contains zero VOC and meets all USDA/FDA guidelines for use in federally inspected facilities.



ROCK-BLOCK 3K Moisture Barrier is to be installed as provided, directly to properly prepared concrete substrates where moisture vapor drive is suspected or has been identified through testing procedures. ROCK-BLOCK 3K Moisture Barrier deeply penetrates and bonds into concrete slabs to help lock down moisture and prevent moisture vapor drive from causing blistering or delamination in the floor finish. ROCK-BLOCK 3K Moisture Barrier is the best primer for most ROCK-TRED polymer flooring systems, but can also be used to reduce MVER to levels that allow other floor finishes such as VCT, PVC sheet-goods, carpet tiles, rubber matting, etc. to be installed. ROCK-BLOCK 3K Moisture Barrier CAN BE APPLIED TO PROPERLY PREPARED CONCRETE WITH READINGS OF UP TO 99% RH per ASTM F2170. Contact ROCK- TRED for MVER questions when using ASTM 1869.


Typical Coverage

ROCK-BLOCK 3K Moisture Barrier is recommended to be applied in one application of 16 mils (100 square feet per gallon) over an ICRI CSP 3 concrete profile to create a fully sealed, pin-hole free finish with a CLASS 1 PERMEABLITY RATING. It is critical that the material be applied evenly and that a PIN-HOLE FREE finish is achieved to provide an appropriate level of impermeability.


Physical Properties

Volume mix ratio Mix Full Kits ONLY
Viscosity (mixed) 1800 - 2400 CPS Typical (With Part C)
Solids Content (%) 100% (ASTM D-2697)
VOC 0 g/l (EPA method 24)
Hardness (ASTM D-2240) 70-80 (Shore D)
Application Temps. 55° – 85°F
Gel Time 25 - 30 minutes @ 75° F
Dry to Touch (recoat with ROCK-BLOCK Moisture Barrier) 2 - 4 hours @ 75° F
Through Cure (recoat with compatible finish coat) 5 - 8 hours @ 75° F
Open for Light Traffic 24 hours @ 75° F
Shelf Life 1 Year in unopened units

Limitations & For Best Results

  • Do not thin this product.
  • Do not apply when humidity exceeds 70% indoors.
  • Allow each coat to dry to 'tack-free' or clear prior to re-coat.
  • When re-coating, always apply the next coat within 24 hours of completing the previous coat.
  • Review and understand the Rock-Block Product Installation Tech Bulletin prior to applying this system. Follow the instructions provided therein for mixing, application, patching, recoating, etc.
  • Shot-blast preparation is recommended. If preparation is performed via diamond grinding and is not thorough enough to reduce surface tension separation of the coating may occur. If separation occurs and cannot be rolled out allow the material to dry, sand the separated area, wipe with MEK and recoat.
  • Always apply as provided and do not tint or fill or broadcast with any material other than the Part C provided.
  • Perform a thorough site inspection and perform ASTM F2170 and ASTM F710 to determine the present condition of the slab to be coated.
  • DO NOT SPLIT KITS – mix the entire unit.

Product Application

To mix, add all Part C into resin and power mix on low speed (300 RPM) until fully blended. While mixing, scrape down the sides and bottom of mixing vessel to free settled clumps of Part C. Add Hardener and continue to mix for 2-3 minutes. Apply by brush, squeegee and ½ inch nap roller at 100 sq. ft./gal. to create a uniform 16 mil thick pinhole free finish. If air bubbles are seen after the first coat, cut off the bubble and apply material to fill the pinhole or other porous areas. Extremely porous concrete may require additional coats to completely seal the surface.


Color and Textures

ROCK-BLOCK liquids are manufactured in Clear (light straw) and will dry to a black color when applied with the Part C component. DO NOT add any other broadcast media, colorants or fillers besides the Part C.


Chemical Resistance

ROCK-BLOCK 3K has above average chemical resistance. Always choose an appropriate ROCK-TRED finish coating with proper chemical resistance levels if required. Always refer to ROCK-TRED's chemical resistant chart for specific information on each product / system or contact ROCK-TRED directly.


Product Storage

DO NOT allow ROCK-TRED products to freeze. All ROCK-TRED products should be properly stored above the floor on pallets or shelves, and in an area that has a constant minimum temperature of 50°F.


Surface Preparation

Always apply ROCK-TRED products to a clean / sound substrate that is free of laitance, grease, oils, debris, and curing compounds. Concrete substrates should be properly cured per ACI 302 and should have reached 98% of its total strength prior to application of product [except as otherwise noted on the individual Product Data Sheet]. Always remove all coatings/floor finishes completely to expose bare concrete. If the substrate is not properly prepared and the appropriate profile is not achieved, failure of the product to adhere to the substrate and perform per specifications may occur. Mechanical preparation by means of shot-blasting to a minimum CSP-3 profile is the best and recommended preparation method for ROCK-BLOCK applications. Shot-blasting is the preferred method of breaking down surface tension on floors that exhibit high RH. Diamond grinding can be employed when shot-blasting is not possible, but the user must take care to insure that the surface tension has been reduced. Failure to do this can result in areas of separation that resemble fisheyes. This is caused when the material is prevented from penetrating the concrete, or when contaminants such as sealers used in the original curing of the concrete have not been completely removed, or when other contaminants are still present in the concrete. ROCK-TRED strongly suggests applying a sample to the prepared concrete to make sure that the surface tension has been reduced sufficiently enough to allow even and full penetration. If separation does appear the contractor must make sure to recoat these areas before continuing with the installation of the specified flooring material.



ROCK-BLOCK 3K is supplied with ROCK-TRED's Standard Warranty at time of purchase. An extended 5 year ROCK-BLOCK Warranty is available through ROCK-TRED. Please contact ROCK-TRED directly for more information regarding how to obtain an extended ROCK-BLOCK Warranty.


Clean Up

Application tools and equipment should be cleaned with typical epoxy solvents.



Clear epoxy concrete sealer containers will contain product residue and must be disposed of properly. Label warnings must be observed at all times. All containers must be disposed in accordance with federal, state, and local regulations.


Important Notice

Always read and acquaint yourself with ROCK-TRED's Product Data Sheet, SDS [safety data sheet], and product labels for each individual product prior to mixing and prior to use. For further assistance, product questions, additional information and/or unexpected or unusual installation conditions – contact your Area Sales Representative or ROCK-TRED directly for recommendations. Kit components are pre-measured for optimal performance. Catalyzation errors due to incorrect mixing in the field voids product warranty.


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