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Technical Data Sheet (TDS)

VPU-155 "S" Urethane Sealer

Urethane Concrete Sealer

Special features

  • Requires no moisture testing (some restrictions apply)
  • Use prior to Urethane or Polymer products
  • Protects against alkalinity migration

Product Description
STAUF VPU-155 Urethane Sealer is a pure urethane-based sealer for professional flooring installation. It does not contain any solvents, water, or other harmful materials. It is, therefore, ozone and environmentally safe, certified as "very low emissions", and certified "green". VPU-155 is uniquely developed to mitigate the moisture pressure from a humid subfloor to an acceptable level for flooring installation and to bridge minor cracks in the subfloor. VPU-155 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 subfloor. Read and understand all applicable guidelines and technical data sheets before installation. Follow industry standards and flooring manufacturers' recommendations for subfloor moisture content, design, layout, and application of flooring materials. All flooring material's backing must be solid, sound, and free of anti-adherents. All slab constructions must meet the specific requirements of the floor covering to be installed.
Sub Floor Examination
Prior to installation, the subfloor must be checked according to applicable installation guidelines. It must be solid, sound, clean, porous, free of chaps, anti-adherents, and resistant to pressure and tension. Confirm sufficient porosity by performing a 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 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.
Moisture content in concrete subfloors must be below 8#/24hr/1,000SF 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.
No moisture testing is required for installation in new construction as long as a new STAUF #10 disposable 22 in trowel blade is used for every ten pails (maximum) or a new #10 trowel is used for every five pails (maximum); there is 100% coverage of the sealer on the subfloor; the spread rate does not exceed 80 SF/gal and concrete floors are at least 30 days old.

The following conditions MAY NOT be present: Hydrostatic pressure, Excessive vapor emissions, Missing or compromised vapor barrier, Standing water or visible dampness, Uneven and/or unapproved subfloor materials, Improper substrate preparation, Excessive exterior water (damaged water pipes, sinks, icemakers, faulty plumbing, flooding, etc.), Excessive topical moisture, improper ventilation or conditioning, or faulty maintenance of the flooring.
Do not apply the product to a visibly damp surface. Examine concrete subfloor for color, cleanliness, porosity, and pre-existing residues PRIOR TO installation (for details, see Technical Information #18 @ Concrete subfloors must be checked for contaminants and/or anti-adherents using the STAUF Epoxy Test Kit (for details, see Technical Information #16 @
Sub Floor Preparation
The condition of the subfloor 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. The extent of subfloor preparation can only be determined at the site by the installer. Clean the surface with an industrial vacuum cleaner and tack the floor with a damp microfiber 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 the appropriate applicator. Make sure the sealer is spread evenly. Do not exceed the maximum coverage. Higher temperatures speed up the drying time.
Do not transport below 14°F. Store dry and protect from freezing.
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 dilute primer/sealer or mix with other products.
In case of an accident, injury, spill, or exposure, see SDS for information. Consult the Technical Data Sheet at for updated information.
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. 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
  • Moisture cured urethane
  • LEED qualified
  • Dries in less than 2 hours
  • Contains no water
  • Contains no solvents
  • Contains no VOC (calc. per CA Rule 1168)
  • Nonflammable
  • Ozone friendly
  • Freeze/thaw stable
Installation Features
  • Very low odor
  • Cleans with acetone
  • Spreads easily
  • Good penetration of subfloor
  • Dries quickly
  • Higher temp will shorten drying time
  • Suppresses minor cracks in concrete slabs
Long Term Features
  • Improves bonding of STAUF urethane-based adhesives
  • Improves bonding of STAUF polymer adhesives
  • Moisture barrier up to 25# or 100% RH using XBL10
  • Suitable for radiant heat systems
Approved Subfloors
  • Concrete Slabs
  • Ceramic Tiles
  • Stone, Terrazzo
Approved Trowels and Spread Rate
  • Sealer: XBL10 (7/64 x 5/64 in): up to 80 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
  • Brown
pH value of concrete
  • Resistant up to 14
  • Dry
Shelf Life
  • 12 Months in original, unopened container
Revision: 2021-08-24 10:10:21

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