Available Sizes
  • 3 Gallon BAG-PAKTM Unit in a single pail
  • Original ROCK-BLOCK is available as a special order product. Allow 2-5 days lead time when ordering.
  • 100% solids
  • Cost effective
  • Excellent adhesion
  • 0 VOC, no solvent odor
  • 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 Moisture Barrier, also known as "Original" or "ROCK-BLOCK 2K", is a 100% solids, two-component, high-performance epoxy primer 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 Moisture Barrier achieves a CLASS I VAPOR RETARDER rating of 0.1 PERM OR LESS per ASTM E96-14. ROCK-BLOCK Moisture Barrier contains zero VOC and meets all USDA/FDA guidelines for use in federally inspected facilities.



ROCK-BLOCK Moisture Barrier is to be installed as a neat coating directly to properly prepared concrete substrates where moisture vapor drive is suspected or has been identified through testing procedures. ROCK-BLOCK 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 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 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 Moisture Barrier is recommended to be applied in two successive applications of 150 - 200 square feet per gallon per coat to create a fully sealed, pin-hole free finish with a CLASS 1 PERMEABLITY RATING. One 16 mil application of ROCK-BLOCK Moisture Barrier is possible, but the finish must be PIN-HOLE FREE to provide an appropriate level of impermeability.


Physical Properties

Volume mix ratio Mix Full Kits ONLY
Viscosity (mixed) 700 - 1000 CPS Typical
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 10 - 20 minutes @ 75° F
Dry to Touch (recoat with ROCKBLOCK 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' prior to re-coat.
  • When re-coating, always apply the next coat within 24 hours of completing the previous coat.
  • Always apply as provided and do not tint or fill or broadcast with any material except when patching per the Rock-Block Product Installation Tech Bulletin.
  • Perform a thorough site inspection and perform ASTM F2170 and ASTM F710 to determine the present condition of the slab to be coated.
  • If slab contamination may be present core sampling and proper core analysis is strongly recommended prior to start of work. Contact ROCK-TRED for more information on this process.
  • 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 acetone and recoat.
  • DO NOT SPLIT KITS – mix the entire unit.

Product Application

Apply by brush, squeegee and ½ inch nap roller to create a uniformly thick and 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 prior to applying a second coat. ROCK-TRED product test data is based on environmental temperatures of 75° F. Viscosity and working time are always affected by temperatures above or below that mark. When applying product always consider the ambient, surface, and product temperature at the time and place of installation.


Color and Textures

ROCK-BLOCK Moisture Barrier is manufactured in Clear (light straw) ONLY and cannot be field pigmented or broadcast to add texture.


Chemical Resistance

ROCK-BLOCK Moisture Barrier is not intended for use as a finish coat. 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 Moisture Barrier is supplied with ROCK-TRED's Standard Warranty at time of purchase. An extended 5 year ROCKBLOCK Warranty is available through ROCKTRED. 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.



Product 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.


Related Videos

Chris O'Brien, President/CEO of Rock Tred talks about Rock Tred's Rock Block Primer and its superior performance under comparative testing.