Moisture, Crack Isolation & Sound Barrier Membrane – Bostik MVP4 (5 Gal)

Bostik MVP4 is the heavy-duty "insurance policy" for flooring contractors and developers dealing with high-humidity concrete slabs or second-story installations. This one-part moisture-cure urethane membrane serves a triple purpose: it significantly reduces moisture vapor transmission from the subfloor, acts as a noise reduction barrier, and functions as an anti-fracture membrane that can bridge cracks up to 1/8". It is applied via trowel directly to the concrete before a glue-down wood floor installation to prevent future buckling or sound complaints in multi-family units. By using MVP4, you achieve a professional-grade foundation that allows for a "dry" warranty even on problematic subfloors, ensuring your hardwood investment is protected from the bottom up.

Bostik MVP4® is a high-performance, one-part, moisture-cure urethane membrane designed for glue-down hardwood flooring installations. It provides unlimited moisture vapor protection, crack isolation, and premium sound reduction in one easy-to-apply system.

MVP4® forms a flexible elastomeric membrane that bridges substrate cracks up to 1/8 inch, while allowing natural movement from temperature and humidity changes. It also acts as a sound-control layer that can outperform ¼” cork underlayment when installed with Bostik’s BEST® adhesive.

Key Benefits

• Unlimited moisture vapor protection
• Anti-fracture membrane bridges cracks up to 1/8”
• Sound reduction comparable to 1/4” cork underlayment
• One-part urethane – no mixing required
• Low VOC (less than 73 g/L)
• Zero water content
• Built-in antimicrobial protection against mold and mildew
• Visual inspection of membrane before installing flooring

Designed For

• Solid hardwood
• Engineered hardwood
• Bamboo
• Cork
• Parquet

Approved substrates:

• Concrete, cement patch & underlayments, plywood, OSB

Sound Control Performance

(when used with Bostik BEST adhesive)

• Over 6” concrete with 9/16” engineered wood and 5/8” gypsum ceiling:
  • 62 IIC / 61 STC
• Over 6” concrete with 9/16” engineered wood, no ceiling:
  • 49 IIC / 52 STC

Installation & Coverage

• Apply with 3/16” x 5/32” V-notch trowel
• Creates 30 mil minimum membrane
• Coverage: 40–45 sq. ft. per 5-gallon pail
• Cure time: 12–16 hours before flooring installation
• Working time: up to 180 minutes
• Color: Grey

Moisture Protection

• Water vapor permeability: < 0.4 perms
• No moisture limits when slab is dry to the touch
• Eliminates the need for separate moisture testing when used with approved adhesives

Physical Properties

• Elongation: 180%
• Service temperature: -40°F to 150°F
• Density: 12.2 lbs per gallon
• VOC compliant
• Easy troweling
• Mild odor

Packaging

• 5-gallon metal pail
• 36 pails per pallet