Master Wall® Bagged Base Coat (MBB) is a dry polymer acrylic formulated high performance base coat and adhesive used in Master Wall® Systems
or over prepared substrates including brick, masonry, concrete and stucco.


  • Adheres insulation board to approved substrates
  • Base coat for Master Wall CIFS®, EIFS and other Systems
  • Leveling coat for Cemplaster Fiberstucco and other stucco products
  • Excellent water resistance
  • Freeze stable in dry form
  • Convenient, mixes with water
  • Easy clean up with water

Application Temperature: 40°-110°F (5°-43°C)
Working Time: 1 hour
Set Time: Varies with temperature and humidity
Dry Time: 12 hours at room temperature, working and drying time will vary with temperature and humidity.

Coverage per bag (sf/sm)*
Adhesive & Standard Base Coat: 50-60 sf (4.6-536 sm)
Embedding Single-layer of Mesh: 100-125 sf (9-11.5 sm)
Double Layer of Mesh: 30-110 sf (2.5-10 sm)
Notched Trowel Adhesive Application: 56 sf (5.2 sm)
*All coverage is approximate and depend upon substrate, details and individual application

Packaging/Shelf Life/Storage
Packaging: 50lb (22.7kg) bag
Shelf Life: 1 year
Storage: Protect from weather, high humidity and direct sunlight.

Air and substrate temperature for application of MBB must be 40°F (5°C) or higher and must remain 40°F (5°C) or higher for a minimum of 24 hours. Provide temporary protection to protect the wall system from damage until permanent flashings, caps and sealants are installed. Store materials within prescribed temperature limits and out of direct sunlight. Working and drying times are based upon normal room temperature conditions and will vary with temperature and humidity.

The substrate must be approved by Master Wall Inc®., clean, dry, structurally sound and free of efflorescence, oil, grease, form release agents and curing compounds or anything that would affect bond. Painted surfaces are generally unacceptable without evaluation.

Mixing – Add 5 to 6 quarts (4.7-5.7L) of potable water to a clean plastic pail.  Add the MBB slowly while stirring using a heavy-duty 1/2” (12.7mm) drill at 400 to 500 rpm and a heavy-duty Mixer. Mix thoroughly to a homogenous consistency. Let the mixture stand for 3 to 5 minutes and then stir to a creamy consistency. Small amounts of clean, potable water may be added to obtain a workable consistency. Do not over mix. Excessive stirring may cause faster setting and reduced working time. Do not add accelerators or retarders to the MBB mixture.

ADHESIVE APPLICATION – Over gypsum or Rollershield coated substrates, apply the MBB mixture directly to the back of the insulation board using a 3/8” x 3/8” x 3/8” (9.5 x 9.5 x 9.5 mm) or a 3/8” x 1/2” x 1-1/2” (9.5 x 13 x 38 mm) stainless steel notched trowel. With the trowel at a 45-degree angle, cover the entire back of the insulation board with full beads of adhesive. Apply the adhesive so the ribbons run vertically when applied to the wall.

Over non-gypsum substrates where drainage is not required, you may use the above described notched trowel method or the ‘ribbon and dab’ method. Using a stainless steel plastering trowel, apply a 2” (50.8 mm) wide by 3/8” (9.5 mm) high ribbon of the F&M mixture around the entire perimeter of the insulation board. Place 8 dabs of the F&M mixture 3/8” (9.5 mm) thick by 4” (102 mm) in diameter approximately 8” (204 mm) on center inside the ribbon.

Immediately place the prepared insulation board on the substrate. Make sure that all edges of the insulation board are abutted tightly and that no F&M mixture gets into the board joints. Do not allow the MBB mixture to form a skin prior to placing the insulation board on the substrate. Do not apply the MBB mixture directly onto the substrate.

BASE COAT APPLICATION – Over insulation board, all imperfections in the board must be rasped flush and any gaps in the insulation board must be filled with slivers of insulation. Apply the MBB mixture 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 MBB mixture 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.

As a leveling coat over approved concrete, masonry, stucco, and other surfaces, apply the MBB mixture over the entire surface a nominal 1/16” (1.6 mm) thick. Where reinforcing mesh is specified, follow application methods for insulation board above.

Tools and equipment can be cleaned with soapy water while the MBB is still wet.

If sanding or scraping are performed, ventilate work area and/or use a NIOSH/MSHA-approved respirator in accordance with our Safety Data Sheet.

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. ©2022 Master Wall Inc.®

Additional Information

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MBB SDS Mexican Spanish


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.

Approved Substrates
Exterior gypsum sheathing
(ASTM C1396, C1177)
Dens Glass Gold®
Gold Bond e2xp®
Weather Defense Platinum™
Cement Board (ASTM C1325)
Metal Lath – Adhesive Application
Adheres to Rollershield
Others approved in writing