To finish strong you need a versatile base coat. EPSB is a 100% pure acrylic one-part, fibered, 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.


VOC: <1% by Weight Manufacture Locations: 30058 • 77474 • 84651 Recycled Content: 0%


Single Layer Mesh Only: 110-130 sf (10-12 sm)

*Coverages are estimated and vary

Weight: 60 lbs (27 kg)

Working Time: Working Time: 1 hour @ room temperature

Drying Time: 12 hours under normal room temperature and humidity.

Application/Storage Temperatures: 40°F (5°C) to 110°F (43°C)

Shelf Life: 2 years under normal conditions.

Approved Substrates

  • Master Wall® Insulation Board
  • Painted Surfaces** with appropriate testing – see Technical Bulletin
  • Others approved in writing

Application Procedure

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.

Surface Preparation – 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 ½ inch (12.7 mm) drill at 400 – 500 rpm and a heavy duty mixer. Small amounts of clean, potable water may be added to obtain a workable consistency.  Do not over mix. Do not exceed 12 ounces (0.35L) 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 inch (1.6 mm)  for standard mesh and 3/32 inch (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 to 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 while the EPSB is still wet.


Do not over mix.

Make sure that the EPSB coat is completely dry prior to the application of Master Wall® Superior Finish Coat.
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