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Technical Data Sheet (TDS)

ACS-210 True-Seal

Acrylic Concrete Sealer / Primer

Special features

  • Moisture barrier up to 8# or 85% RH
  • Use as Primer over Epoxy Sealer
  • Use prior to any STAUF leveling compound or adhesive
  • Patent No 8,680,193

Product Description
STAUF ACS-210 True-Seal is a pure acrylic based sealer for professional flooring installation. It does not contain any solvents, isocyanates or other harmful materials. It is therefore ozone and environmentally safe, is certified as "very low emissions", and is certified "green". ACS-210 is uniquely developed to mitigate the moisture pressure from a humid sub floor to an acceptable level for flooring installation and to bridge minor cracks in the sub floor. ACS-210 spreads easily and creates a dust free and evenly absorbent surface ready for installation of flooring. It has superior coverage and dries very quickly.
Pre-Installation Checklist
A successful installation requires proper preparation of the sub floor. Read and understand all applicable guidelines and technical data sheets before installation. Follow industry standards and flooring manufacturer's recommendations for sub floor moisture content, design, layout and application of flooring materials. Backing of all flooring material must be solid and sound and free of any anti-adherents. All slab constructions must meet the specific requirements of the floor covering to be installed.
Sub Floor Examination
Prior to installation, the sub floor must be checked according to applicable installation guidelines. It must be solid and sound, flat, permanently dry, clean, free of chaps, indentations and anti-adherents, as well as resistant to pressure and tension. Moisture content of all floors must be measured before installation.
Moisture content in concrete sub floors must be below 8#/24hrs/1,000 sq. ft. using the Calcium Chloride Test or less than 85% RH using the in-situ test per ASTM F1869 and F2170. Use epoxy moisture barrier for higher moisture installations.
Prior to installation, the sub floor must be checked according to applicable installation guidelines. It must be solid and sound, clean, porous, free of chaps and anti-adherents, as well as resistant to pressure and tension. Confirm sufficient porosity by performing water drop test according to ASTM F3191-16. Check for missing or compromised vapor barriers and hydrostatic pressure by carrying out RH or CaCl moisture tests following ASTM standards F1869-16 or F2170-19. Results of 99% RH or 25# CaCl could indicate that there is a higher moisture content in the slab than what tests can measure and there might be hydrostatic pressure and/or a compromised or missing vapor barrier.
Sub Floor Preparation
The condition of the sub floor will determine which type of mechanical treatment is required (e.g. wire brushing, sanding, grinding or shot blasting). Dust, paint, curing compounds, sealers, residual adhesives or other surface contaminants MUST be removed and a porous surface achieved by suitable means. Extent of sub floor preparation can only be determined at the site by the installer. Clean the surface with an industrial vacuum cleaner, tack floor with damp micro fiber mop before application. Do not use sweeping compounds unless they are water based as most others will contain oil or wax which will act as an anti-adherent and prevent primers, sealers, leveling compounds, coatings and/or adhesives from bonding to the concrete. Cracks and gaps must be treated prior to application of primers, sealers, leveling compounds, coatings and/or adhesives (for details see Technical Information #19 @
Installation Procedure
Shake before use and apply sealer undiluted with appropriate applicator. Make sure sealer is spread evenly. Do not exceed the maximum coverage. Higher temperatures will speed up the drying time.

Store and transport protected from freezing. Recommended minimum temperatures are 35 °F for transport and 40 °F for storage. Do not stir product if frozen, allow to thaw completely.
When using other than STAUF products in conjunction with STAUF primers, sealers, leveling compounds, or adhesives, STAUF denies any and all responsibility for any ensuing problems and/or damages without prior written authorization from STAUF.
Do not use on sub floors with a moisture reading above 8#/24hr./1,000 sq. ft. (Calcium Chloride Test) or 85% (RH with in-situ probe)

In case of accident, injury, spill or exposure, see SDS sheet for information. Consult technical data sheet at for updated information.
Do not dilute primer/sealer or mix with other products.
The foregoing representations are based on the results of our most current product and material testing within a controlled environment and are of a non-obligatory advisory nature only. As such, they do not constitute an express or implied warranty of any kind including the Warranty of Merchantability and/or Fitness for a Particular Purpose. Because we have no control over the actual quality of workmanship, materials used and worksite conditions, STAUF USA, LLC. will in no event be liable for any incidental and/or consequential damages. herefore, we strongly recommend that prior on-site testing be conducted to refer to and study the suitability of the product for the intended purpose. With the release of this technical information sheet all its prior versions become invalid. For warranty and warranty disclaimer information please see our Limited Lifetime Warranty @
General Features
  • works under any type of flooring
  • dries in less than 2 hours
  • contains no solvents
  • contains no VOC (calc. per CA Rule 1168)
  • nonflammable
  • ozone friendly
  • dispersion base cleans with water
  • works under any STAUF adhesive
  • bridges cracks
  • freeze/thaw stable (with limitations)
Installation Features
  • very low odor
  • cleans with warm water and soap
  • spreads easily
  • good penetration of sub floor
  • dries quickly
  • higher temp will shorten drying time
  • suppresses minor cracks in concrete slabs
  • No risk of sensitization
Long Term Features
  • improves bonding of STAUF leveling compounds
  • improves bonding of STAUF water based adhesives
  • improves bonding of STAUF alcohol based adhesives
  • improves bonding of STAUF urethane based adhesives
  • improves bonding of STAUF polymer adhesives
  • moisture barrier up to 8# or 85% RH using XBL10
  • suitable for radiant heat systems
  • No health hazards
Approved Sub Floors
  • Concrete Slabs
  • Wet Concrete Slab up to 8#/24hrs/1,000SF and 85% RH
  • Epoxy Sealers (100% solid, cured)
Approved Trowels and Spread Rate
  • Sealer: XBL10 (7/64 x 5/64 in): up to 80 SF/gal.
  • Primer: Foam or Short Nap Roller: up to 500 SF/gal
Drying Time
  • approx. 2 hours or until clear
Temperature Range during Installation
  • 50-90F (10-32C)
Relative Humidity Range during Installation
  • 30% - 80%
Packing Size
  • 2-1/2 gal. Plastic Jug
  • 75 per pallet
Density [lbs./gal.]
  • 8.6
  • Cream
pH value of concrete
  • must be below 12.4
  • above 32F (two freeze/thaw cycles down to 10F okay)
Shelf Life
  • 12 Months in original, unopened container
  • above 32F (two freeze/thaw cycles down to 10F okay)
Water Vapor Transmission [ASTM E-96]
  • 0.118 grams / hour * m²
  • 0.58 lbs / 24h * 1000ft²
Permeance [ASTM E-96]
  • 0.27 grams / 24h * m² * mmHg
  • 0.41 grains / h * ft² * inHg
Revision: 2017-03-07 09:56:31

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