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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

Product Description
STAUF ACS-210 True-Seal is a pure acrylic based sealer for professional timber flooring installation. It does not contain any solvents, isocyanates or other materials harmful to one's health. It is therefore ozone and environmentally safe, is certified as "very low emissions", and is certified "green". ACS-210 is uniquely developed to retard the moisture pressure from a humid sub floor to acceptable level for timber 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 timber flooring. It has superior coverage and dries very quickly.

ACS-210 can be used in a nail down installation as long as there are no more than 10 nails penetrating the sealer per m².

In case of a glue-down installation there is no time limit as to how soon after applying the sealer it has to be covered with adhesive as long as the surface remains clean and free of dust.

ACS-210 can be applied as a bonding agent over most epoxy and urethane based sealers by applying a thin layer of ACS-210 with a foam roller over the dried sealer. Make sure to test your individual combination before installation.
Pre-Installation Checklist
A successful installation requires proper preparation of the sub floor. Read and understand all applicable guidelines and technical data sheets before beginning installation. Follow industry standards and flooring manufacturer's recommendations for sub floor moisture content, design, layout and application of flooring materials. 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% using the relative humidity test.

Prior to installation, the sub floor must be checked according to applicable installation guidelines. It must be solid and sound, clean, free of chaps and anti-adherents, as well as resistant to pressure and tension. Check for missing or compromised vapor barriers and hydrostatic pressure. Perform RH or CaCl moisture tests following ASTM standards. 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 pollutants MUST be removed 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 or damp mop floor before application. Cracks and gaps must be treated prior to application of primers, sealers, leveling compounds, and/or adhesives (for details see Technical Information #19 @
Installation Procedure
Shake before use and apply sealer undiluted with a #22 Trowel. Make sure sealer is spread evenly. Do not exceed the maximum coverage. Higher temperatures will speed up the drying time.

Store pail in a cool dry place. Store and transport protected from freezing (0 °C).
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 MSDS 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 Adhesive LLC, will in no event be liable for any incidental and/or consequential damages. Therefore, 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
  • nonflammable
  • ozone friendly
  • dispersion base cleans with water
  • works under any STAUF adhesive
  • bridges cracks
  • freeze/thaw stable (with limitations)
Installation Features
  • very low odour
  • 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 - use XBL10: up to 1.96 m/L
  • Primer: Foam or Short Nap Roller: up to 12.3 m/L
Drying Time before Installation
  • approx. 2 hours or until clear
Temperature Range during Installation
  • 10-30 C
Relative Humidity Range during Installation
  • 30% - 80%
Packing Size
  • 2 gal. (9.46 L)Plastic Jug
  • 75 per pallet
Weight [lbs./gal.]
  • 8.6
  • cream
pH value of concrete
  • must be below 12.4
  • above 0 C (two freeze/thaw cycles down to -10 C okay)
Shelf Life
  • 12 Months in original, unopened container
  • above 0 C (two freeze/thaw cycles down to -10 C okay)
Water Vapor Permeance
  • 0.118 grams / hour * m²
  • 0.58 lbs / 24h * 1000ft²
Water Vapor Permeability
  • 0.27 grams / 24h * m² * mmHg
  • 0.41 grains / h * ft² * inHg
Revision: 2011-04-23 19:29:33

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