Master Wall® MBB Plus is the high-build version of our MBB adhesive and base coat. MBB Plus allows leveling up to 1/4” (6.4 mm) in a single pass.

  • Adheres insulation board to approved substrates
  • Excellent water resistance
  • Freeze stable in dry form
  • Convenient, mixes with water
  • Base coat for Aggre-flex Mesh


VOC: 0
Shipping Locations: 30058 • 77474 • 84651

Packaging: 50lb (22.7kg) bag

Shelf Life: 1 year

Coverage (estimated)

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)

Coverage Per Thickness

1/16” (1.6 mm) – 125 sf (11.6 sm)
1/8” (3.2 mm) – 60 sf (5.6 sm)
1/4” (6.4 mm) – 30 sf (2.8 sm)


Aggre-flex EIFS
Aggre-flex Drainage EIFS
Cemplaster Fiberstucco
ICF Coatings
QRW1 Drainage EIFS
Rollershield Drainage CIFS®
Soffit System
Stucco Cement Board Coatings
Uninsulated Finishes

Approved Substrates

  • Exterior gypsum sheathing (ASTM C1396, C1177), Dens Glass Gold® ,GlasRoc®, FiberBond®, Gold Bond e2xp®,, Securock®, Weather Defense Platinum
  • Cement Board, Durock®, PermaBase®, Util-A-Crete®, ProTEC®, ProGUARD®
  • Concrete
  • Brick
  • Masonry
  • Metal Lath
  • Rollershield over a Substrate

Others approved in writing

Application Procedure

Job Conditions – Air and substrate temperature for application of MBB Plus 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.

Preparation – 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 not acceptable and must be removed.

Mixing – Add 5 to 6 quarts (4.7-5.7L) of potable water to a clean plastic pail. Add the MBB Plus slowly while stirring using a heavy-duty 1/2” (12.7mm) drill at 400 – 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 Plus mixture.

Adhesive application – Over gypsum substrates, apply the MBB Plus mixture directly to the back of the insulation board using a 3/8”x3/8”x3/8” (9.5×9.5×9.5 mm) or a 3/8”x1/2”x1-1/2” (9.5x13x38 mm) stainless steel notched trowel. With the trowel at a 45o 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, 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 MBB Plus mixture around the entire perimeter of the insulation board. Place 8 dabs of the MBB Plus 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 MBB Plus mixture gets into the board joints. Do not allow the MBB Plus mixture to form a skin prior to placing the insulation board on the substrate. Do not apply the MBB Plus mixture directly onto the substrate.

For base coat application – All imperfections in the insulation board must be rasped flush and any gaps in the insulation board must be filled with slivers of insulation. Apply the MBB Plus 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 Plus 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 to Master Wall specifications. The color of the mesh shall not be visible but a slight mesh pattern may be visible. Leveling over Master Wall base coats or other approved substrates to 1/4” (6.4 mm) and can be tapered to a feather edge if needed.

Clean Up—Tools and equipment can be cleaned with soapy water while the MBB Plus 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. ©2018 Master Wall Inc.®

F&M Leveling Base Coat Application (no mesh) (MBB is the same)