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SCHÖNOX® AP Synthetic Gypsum Based Self‑leveling Compound

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Product Name Price Qty
SCHÖNOX® AP Synthetic Gypsum Based Self‑leveling Compound, 55 LBS
Item # EX-SCHAP-55
55 lbs    Qty: 1
Availability: Typically in stock (Details)
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  • EMICODE EC 1PLUS: very low emission
  • For interior use only
  • Self-leveling
  • Very low shrinkage
  • Coverage: Approx. 60–70 sq ft per unit at a thickness of 1/8"

Product Information

SCHÖNOX AP is a synthetic gypsum-based self-leveling compound that is especially suitable on all gypsum- and cement-based substrates as well as on asphalts. It is designed for refurbishment work in interior areas only. SCHÖNOX AP can be installed up to 2”.


SCHÖNOX AP delivers high hardness and strength. It has very low shrinkage and is free of cracks, even in higher thicknesses.


This pumpable compound is easy to apply and does not support mold growth. Users can layer thicknesses above 1/16“ up to 1“ without aggregates or layer thicknesses up to 2“ with aggregates.


SCHÖNOX AP exceeds minimum Ff/Fl requirements of ASTM and ACI when installed in accordance with the guidelines. It has been tested in accordance with ASTM C1708.


This compound is rated EMICODE® EC 1PLUS for very low emissions. It is suitable for castor wheel loadings above 1/16“ according to DIN EN 12529.


SCHÖNOX AP is suitable for filling, smoothing and leveling of substrates:

  • Under flexible coverings
  • Under wood floor, layer thickness at least 1/8“ (use elastic adhesives only)


SCHÖNOX AP is suitable on:

  • Gypsum substrates
  • Concrete, cement substrates
  • Old substrates, such as ceramic tiles, terrazzo, and sheet vinyl
  • Old, water-resistant adhesive residues
  • OSB board, plywood (well screwed and/or bonded) prior to installing flexible coverings
  • Underfloor heating systems


Key Specifications:

  • Pot Life: Approx. 30 minutes
  • Ready for Foot Traffic: Approx. 2 hours
  • Ready for Covering: Approx. 16 hours
  • Working Temperature: Not below 41°F
  • Environmental Product Declaration (EPD): EPD-DIV-2013311-EN
  • LEED—May help contribute to LEED certification of projects in the following categories:
    • EQc2: Low-Emitting Materials – 1 to 3 points
    • MR Credit 1.1: Building Reuse-Maintain – Existing Walls, Floors and Roof – up to 3 points
    • MR Credit 1.2: Building Reuse-Maintain – Existing Interior Nonstructural Elements – 1 point
    • MRc3: Environmentally Preferable Products – 0.5 to 5 points
  • VOC Content: 0g/l (calculated), SCAQMD 1113
  • Shelf Life: 12 months, unopened
  • Coverage
    • Approx. 60–70 sq ft per unit at a thickness of 1/8” (depending on substrate conditions and aggregate used)
  • Compressive Strength (ASTM C109):
    • 5,800 PSI / 35 N/mm² / 400 kg/cm2 after 28 days
    • 2,100 PSI / 13 N/mm2 / 140 kg/cm2 after 1 day
  • Flexural Strength (ASTM C348): Approx. 1,400 PSI / 8 N/mm² after 28 days
  • Tensile Strength (ASTM C1583) at 1/8”: Above 400 PSI / 2.5 N/mm2 after 3 days
  • Initial Set (ASTM C191): Approx. 160 minutes
  • Final Set (ASTM C191): Approx. 200 minutes
  • UL-classified in accordance with ASTM E84 (ANSI/UL 723): Flame Spread 0; Smoke Development 0


* All values are approximate, are subject to local climatic fluctuations based upon conditions at 70°F with atmosphere of less than 65% relative humidity following the recommended mixing ratio. Do not install underlayment or topping before the substrate has dried thoroughly



Mixing Ratio:

Mix each 25kg/55 lbs bag with 6.0 liters/6.3 quarts of water.


If SCHÖNOX US is extended with dry, clean aggregate (aggregate is added last) at a layer thickness of 1”–2“, type and amount of aggregate used will affect product performance. As qualities of locally available aggregates vary, we recommend performing tests prior to use on a larger scale.


Do not overwater! Foam while mixing, or settling of the sand aggregate while placing, indicates overwatering.


Recommended Working Method:

Adequate ventilation is essential when SCHÖNOX AP is being worked to ensure faster drying.

  1. Using a clean mixing drum, add SCHÖNOX AP to cold, clean water to form a homogeneous mixture.
  2. Mix thoroughly for approx. 3 minutes using a heavy-duty drill (min. 600 RPM) is recommended to obtain a lump-free mix.
  3. Pour the mix and spread using a smoothing trowel. Even surfaces are easily achieved using a pin leveler. In higher thicknesses using a spike roller is recommended. Contact to vertical structures should be avoided by putting in an edge strip. Avoid direct contact to metallic constructions (e.g. heating pipes), which can lead to corrosion.
  4. If a second layer of leveling compound is to be applied, prime the first layer with SCHÖNOX VD (diluted 1:1 with water) after drying. The maximum layer thickness must not be exceeded in case of two-layer applications. The second layer must not exceed the layer thickness of the first layer.
  5. Protect curing SCHÖNOX AP layers from high ambient temperatures, direct sunlight and draughts.
  6. Clean tools in water immediately.


More Information
Category Concrete Patch
Brand Schönox
Condition new
Safety Data Sheet (SDS)