To finish strong, you need a versatile base coat. EPSB is a 100% pure acrylic one-part, non-cement base coat and leveler with low alkalinity. EPSB is ready to use after pre-mixing, is tintable and can be color matched to our finishes.


  • Ready to use
  • pH Stable, Low Alkalinity
  • Bright White and Tintable to match Finish Colors
  • Bonds to most Acrylic Coatings and Textured Finishes
  • No pot life, reseal unused material for use the next day
  • Low VOC
  • Water-based – easy clean up with water

Coverage per pail (sf/sm)* 110-130 sf (10-12 sm)

*All coverage is approximate and depend upon substrate, details and individual application

Packaging/Shelf Life/Storage

Packaging: 5-gallon (19 L) pail

Shelf Life: 2 years

Storage: Protect from extreme heat – 90°F (32°C), freezing and direct sunlight.

Hazard: This chemical is not considered hazardous according to the OSHA Hazard Communication Standard 2012 (29 CFR 1910.1200). VOC: Less than 50 g/L.

Application Temperature: 45º-110º F (7º-43º C)

Working Time: 1 hour

Set Time: 8-12 hrs

Dry Time: 48-72 hrs at room temperature, working and drying time will vary with temperature and humidity.

Approved Substrates

Master Wall® Insulation Board

Painted Surfaces*

Master Wall® Base Coats


Prepared & Base Coated Surfaces of: Brick Concrete Masonry

Others approved in writing

* With appropriate testing – see Technical Bulletin


Job Conditions – Air and substrate temperature for application of EPSB must be 45° F (7° C) or higher and must remain 45° F (7° C) or higher for a minimum of 24 hours. Working and drying times are based upon normal room temperature conditions and will vary with temperature and humidity.

Temporary Protection – Must be provided at all times until the EIF System, including flashings, caps, and sealants, is completed to provide protection from climatic conditions and other potential damage.


The Master Wall insulation board must be well adhered to the substrate. All imperfections in the insulation board must be rasped flush and any gaps in the insulation board must be filled with slivers of insulation. Surface temperature must be above 45° F (7° C).


Mixing – Thoroughly stir EPSB using a heavy duty 1/2” (12.7 mm) drill at 400 – 500 rpm and a heavy-duty mixer. A small amount of clean, potable water may be added to obtain a workable consistency. Do not over mix. Do not exceed 12 ounces (0.35 L) of water per pail. Do not add accelerators or retarders to EPSB.

Application – Apply the EPSB over the entire surface of the insulation board in a thickness greater than that of the reinforcing fabric being used, approximately 1/16” (1.6 mm) for standard mesh and 3/32” (2.4 mm) for Ultra Mesh. Immediately embed the reinforcing fabric into the wet EPSB and smooth from the center to the edge to avoid wrinkles. The reinforcing fabric must be continuous at all corners and lapped or abutted in accordance with Master Wall specifications. The color of the mesh shall not be visible, but a slight mesh pattern may be visible.

Clean Up – Tools and equipment can be cleaned with soapy water when the EPSB is wet.


  • Do not over mix.
  • Make sure that the EPSB coat is completely dry prior to the application of Master Wall Superior Finish.
  • Slope surfaces a minimum of 1:2 to shed water.
  • While drying, the EPSB coat must not be in contact with any moisture or localized delamination may occur.

Information contained in this product data sheet conforms to the standard detail recommendations and specifications for the installation of Master Wall® Inc. products and is presented in good faith. Master Wall Inc. assumes no liability, expressed or implied as to the architecture, engineering, or workmanship of any project. This information may be concurrent with, or superseded by other applicable documents, such as specifications and details. Contact Master Wall® Inc. for the most current product information.

Additional Information