VB Vapor & Air/Water Resistive Barrier

R-Guard VB: Liquid-Applied Vapor & Air/Water Resistive Barrier for Above-Grade Wall Assemblies

PROSOCO R-Guard VB is a fluid-applied, spray-grade air and water-resistive barrier engineered for contractors who need reliable protection against air leakage, liquid water intrusion, and water vapor transmission in a single product. Once applied to the substrate, it dries quickly into a rubberized, highly durable, water-resistant membrane that performs the dual function of a vapor barrier and an air/water resistive barrier. It is appropriate for vertical, above-grade applications to exterior sheathing, CMU, cast concrete, and most other common building materials. R-Guard VB is well-suited for cavity wall, masonry veneer, stucco, EIFS, and most other building wall assemblies.

Unlike self-adhered or mechanically fastened sheet wraps, R-Guard VB applies as a seamless liquid membrane with no tears, holes, or improperly lapped joints to compromise performance. The fluid-applied format eliminates air leakage or water intrusion between the sheathing and the membrane, keeping the assembly stable under air and wind pressure loads, while its single-component, water-based formulation means fast installation, water cleanup, low odor, and a long pot life.

Key Features & Benefits

Dual-Function: Vapor Barrier + Air/Water Resistive Barrier

R-Guard VB is engineered to perform as both a vapor barrier and an air/water resistive barrier in a single application, eliminating the need for separate products or layers. This consolidation can simplify specification, reduce material procurement, and streamline wall assembly construction for contractors working on projects with strict moisture and air control requirements.

Seamless, Rubberized Membrane

The liquid application dries into a continuous, rubberized membrane with no seams, laps, tears, or holes — common failure points found in sheet-applied alternatives. This seamless coverage delivers consistent protection across the substrate and simplifies inspection and quality control on the job site.

Weather-Resistant During Construction

R-Guard VB will not tear or lose effectiveness when exposed to weather during the construction process, and may be exposed to weather for up to 6 months without compromising performance. This durability during the construction window reduces the risk of having to reapply or repair the barrier before cladding installation is complete.

Reduces Energy Loss and Moisture Risk

By stopping air leaks through the wall assembly, R-Guard VB reduces condensation and the energy loss associated with uncontrolled air movement. It also lowers the risk of water damage to sheathing and reduces heating and cooling costs, as well as the risk of mold and mildew growth within the wall assembly.

Fast, Easy Spray Application

R-Guard VB is spray-applied, enabling fast and easy installation that reduces labor costs compared to sheet-applied barriers. The single-component formulation, long pot life, low odor, non-toxic chemistry, and water cleanup make it practical for crew use in a wide range of job-site conditions.

Broad Compatibility

The cured membrane is compatible with most paints, sealants, and self-adhered waterproofing or air barrier components, making R-Guard VB straightforward to integrate into a continuous building-wide air barrier system. It conforms and adheres to common building surfaces without requiring extensive additional primers or transition materials.

Common Applications

Cavity Wall and Masonry Veneer Construction

R-Guard VB is designed to stop air and water leakage in cavity wall and masonry veneer assemblies, providing a continuous barrier behind the cladding layer.

Stucco and EIFS Wall Assemblies

The fluid-applied membrane is suitable for use behind stucco and EIFS systems, providing the required air and water-resistive barrier function in those wall assembly types.

Exterior Sheathing Applications

R-Guard VB applies directly to exterior sheathing as a high-performing water-resistive barrier or vapor barrier, replacing sheet-applied house wraps or building wraps on framed construction.

CMU and Cast-in-Place Concrete Walls

The product is appropriate for above-grade vertical application to concrete masonry units (CMU) and cast concrete surfaces, conforming to the substrate texture to create a continuous, adhered membrane.

Continuous Building-Wide Air Barrier Systems

R-Guard VB can serve as the primary fluid-applied component in a continuous building-wide air barrier system, used in conjunction with compatible joint fillers, sealants, and self-adhered transition membranes from the R-Guard product line.

Compatible Materials

• Exterior sheathing
• Concrete masonry units (CMU)
• Cast-in-place concrete
• Most other common building materials (above-grade, vertical applications)
• Most paints
• Most sealants and coatings
• Self-adhered waterproofing components
• Self-adhered air barrier components

Product Documents

• Product Data Sheet
• Safety Data Sheet
• Safety Data Sheet (Spanish)
• Safety Data Sheet (Canadian French)
• VOC Compliance
• Product Test Data
• NFPA 285 Compliant Wall Assemblies
• LEED Verification Letter

Application Instructions

Surface Preparation

1. Apply only to clean surfaces free of contaminants. Chemical residues, surface oxidation, surface coatings, or films may adversely affect adhesion.
2. For pressure-treated or fire-retardant wood and other contaminated surfaces, clean with an isopropyl alcohol wipe and allow to flash off before application.
3. Cap and seal roofing systems or protect the top of walls from water intrusion before and after air barrier system installation. Water intrusion may interfere with bonding and performance of air barrier waterproofing materials.
4. For cast-in-place concrete: ensure the surface is clean, smooth, and free of curing compounds and form release agents. Repair bug holes, honeycombing, and other imperfections with a suitable cementitious mortar. Remove concrete splashes, over pours, grout, or slurry rundown using appropriate mechanical means. Fill and prepare minor imperfections with R-Guard Joint & Seam Filler.

Application

1. Apply at surface and air temperatures between 40°F (4°C) and 110°F (43°C). Follow Hot Weather Precautions if temperatures approach the upper limit.
2. Do not apply below-grade or in locations designed to be continuously immersed in water.
3. Do not use as an exterior finish.
4. Spray-apply R-Guard VB to the prepared substrate, achieving a continuous film at the appropriate wet mil thickness.
5. After application, inspect the surface to ensure the coating is continuous and free of pinholes. Treat any visible pinholes or breaks in the film with additional primary air and water barrier coating.

Technical Specifications

Frequently Asked Questions

Q: Can R-Guard VB be used below-grade or in submerged applications?
A: No. R-Guard VB is not for use below-grade or in locations designed to be continuously immersed in water. It is intended for vertical, above-grade applications only.

Q: How long can R-Guard VB be left exposed to weather before cladding is installed?
A: R-Guard VB may be exposed to weather for up to 6 months without compromising performance, providing contractors flexibility during the construction schedule.

Q: Is R-Guard VB compliant with VOC regulations?
A: Yes. R-Guard VB has a VOC content of 45 g/L and is compliant with California Air Resources Board (CARB) 2007 regulations. It is also compliant with the US EPA's AIM VOC regulations. Contractors should verify compliance with specific local district or state regulations at prosoco.com/voc-compliance.

Q: Does R-Guard VB support LEED project documentation?
A: Yes. PROSOCO provides submittal information supporting LEED 2009 and LEED v4 documentation, as well as CALGreen, Living Building Challenge 3.x, WELL v2, and Fitwel. A LEED Verification Letter and related documentation are available for download above.

Q: What preparation is required for cast-in-place concrete surfaces?
A: Concrete must be clean, smooth, and free of curing compounds and form release agents. Bug holes, honeycombing, and surface imperfections should be repaired with a suitable cementitious mortar. Minor imperfections should be filled with R-Guard Joint & Seam Filler prior to application.

Q: Is R-Guard VB compatible with other R-Guard system components?
A: Yes. R-Guard VB is compatible with most paints, sealants, and self-adhered waterproofing or air barrier components, and can be used as part of a continuous building-wide air barrier system. Illustrations depicting use with other PROSOCO R-Guard products are available by downloading the R-Guard Installation Guidelines at prosoco.com.