R Guad Cat 5 ICF Fluid Applied Air & Water Barrier Membrane

PROSOCO R-Guard Cat 5™ ICF — Fluid Applied Air & Water Barrier Membrane for ICF and Exterior Assemblies

PROSOCO R-Guard Cat 5™ ICF is a single-component, fluid applied, elastomeric air and water barrier membrane engineered for use on insulated concrete forms (ICF), exterior sheathing, CMU back-up walls, and precast concrete. Based on Silyl-Terminated-Polymer (STP) chemistry, it combines the best properties of silicone and polyurethane to produce a seamless, highly durable weatherproofing membrane. Designed for the demanding requirements of the commercial and residential building envelope, it delivers immediate waterproofing on application and maintains performance for the life of the building. It is ABAA (Air Barrier Association of America) approved.

Unlike two-component systems or traditional sheet-applied barriers, Cat 5™ ICF is a single-component roller-applied product that bonds to most common building materials without priming, self-seals fastener penetrations, and can be applied in unfavorable weather conditions to dry or damp substrates — eliminating weather-related construction delays and accelerating building dry-in. Its STP chemistry means no isocyanates, no solvents, and no phthalates, with no shrinkage, staining, or yellowing over time.

Key Features & Benefits

Hurricane-Rated Wind and Water Resistance

Cat 5™ ICF is proven to prevent air and water penetration in conditions ranging from everyday weather to the drenching rains and 155 mph winds of a Category 5 hurricane. For contractors building in coastal or high-wind zones, this level of verified performance provides confidence that the building envelope will hold under the most extreme conditions.

Bonds and Cures on Damp Substrates in Wet Weather

The membrane adheres and cures even in wet weather and on damp substrates, a critical advantage on active job sites where waiting for ideal conditions is not practical. This feature directly reduces weather-related construction delays and accelerates the drying-in of new buildings.

Silyl-Terminated-Polymer (STP) Technology

The silane functional polymer provides superior long-term adhesion, crack-bridging, and weathering characteristics compared to conventional polyurethane or acrylic membranes. It self-seals fastener penetrations, creating an uninterrupted barrier without additional detailing steps at mechanical fasteners.

Immediately Waterproof — Up to 12 Months UV Exposure

Cat 5™ ICF is waterproof on application and can be fully exposed to UV and weather for up to 12 months, providing flexibility in construction sequencing without requiring immediate cladding installation. The membrane will not tear or lose effectiveness when exposed to weather during construction.

Single Component — Easy Roller Application

As a single-component product, Cat 5™ ICF saves mixing time and eliminates ratio errors associated with two-component systems. It applies easily by roller in all climates, reducing labor complexity and training requirements on the job site.

Breathable and Compatible with Rain Screen Construction

With a water vapor transmission of 18 perms (ASTM E 96), the membrane is breathable, allowing damp surfaces to dry and preventing moisture accumulation within the wall assembly. Cat 5™ ICF meets the requirements for pressure-equalized rain screen construction for use on exterior sheathing behind open-jointed or vented rain screen cladding.

Solvent Free, Isocyanate Free, Phthalate Free

The formulation contains no solvents, isocyanates, or phthalates, and has a VOC content of less than 30 g/L, compliant with the US EPA AIM VOC regulations. This reduces health and safety concerns during application and supports projects with strict environmental compliance requirements.

No Shrinkage, No Staining, No Mold Support

Cat 5™ ICF will not shrink, stain, or yellow after curing, and it will not support mold growth — important for long-term wall assembly integrity and maintaining interior air quality.

Common Applications

Insulated Concrete Form (ICF) Walls

Cat 5™ ICF is specifically designed for ICF construction, providing a seamless, durable air and water barrier across the exterior surface of insulated concrete form assemblies.

Exterior Sheathing

Applied directly to exterior sheathing panels, Cat 5™ ICF creates a continuous weatherproofing membrane suitable for use behind open-jointed or vented rain screen cladding systems in pressure-equalized rain screen construction.

CMU Back-Up Walls

Cat 5™ ICF bonds to concrete masonry unit back-up walls (after a minimum 3-day mortar joint cure) to deliver air and water barrier continuity across masonry substrates.

Precast Concrete

The membrane adheres to precast concrete surfaces, providing seamless waterproofing and air barrier performance across precast wall panel assemblies.

Pressure-Equalized Rain Screen Construction

Cat 5™ ICF meets the unique requirements for pressure-equalized rain screen construction, making it appropriate for use as the drainage plane behind ventilated cavity rain screen cladding systems.

Compatible Materials

• Insulated concrete forms (ICF)
• Exterior sheathing panels
• CMU (concrete masonry unit) back-up walls
• Precast concrete
• Most common building materials (bonds without priming)
• Most sealants
• Most waterproofing and air barrier components

Product Documents

• Product Data Sheet
• Product Data Sheet (Canadian French)
• Product Data Sheet (Spanish)
• Safety Data Sheet
• Safety Data Sheet (Spanish)
• Safety Data Sheet (Canadian French)
• VOC Compliance
• ABAA Certification
• Product Test Data

Application Instructions

Surface Preparation

1. Protect all people, vehicles, property, plants, and surfaces not intended for application. Cat 5™ ICF bonds tenaciously — carefully mask all adjacent surfaces not to be treated.
2. Apply to clean surfaces free of contaminants. Chemical residues, surface oxidation, surface coatings, or films may adversely affect adhesion.
3. Clean pressure-treated wood and other contaminated surfaces with an isopropyl alcohol wipe and allow to flash off before application.
4. Concrete must be in place 3–7 days and free of any curing compounds or form release agents before application.
5. Mortar joints in CMU construction must have a minimum 3-day cure before treatment.
6. For ICF wall assemblies, follow the ICF cleaning procedure detailed in the full Product Data Sheet prior to application.

Application

1. Apply by roller. Product is suitable for roller application in all climates.
2. May be applied to dry or damp substrates in unfavorable weather conditions.
3. Membrane is immediately waterproof upon application.
4. Allow transfer-free time of 2–4 hours before covering or contact with other materials.
5. Product may be fully exposed to UV and weather for up to 12 months. If longer exposure is anticipated, contact PROSOCO for inspection guidance.

Cleanup

1. Immediately clean up incidental contact using mineral spirits or a similar solvent.

Technical Specifications

Safety Data Summary

Safe Handling

• Always read the full label and Safety Data Sheet (SDS) for complete precautionary instructions before use.
• Use appropriate safety equipment and job site controls during application and handling.
• Flash point is greater than 200°F (>93°C).
• 24-Hour Emergency Information: INFOTRAC at 800-535-5053.
• Immediately clean up incidental skin or surface contact using mineral spirits or a similar solvent.

Frequently Asked Questions

Q: Can Cat 5™ ICF be applied in rain or on wet substrates?
A: Yes. Cat 5™ ICF is specifically formulated to bond and cure in wet weather and on damp substrates, eliminating many weather-related construction delays.

Q: How long can Cat 5™ ICF remain exposed to UV and weather before cladding is installed?
A: The membrane may be fully exposed to UV and weather for up to 12 months. If a longer exposure period is required, contact PROSOCO for an inspection.

Q: Can Cat 5™ ICF be used as a liquid flashing membrane?
A: No. Cat 5™ ICF is not intended for use as a liquid flashing membrane. PROSOCO R-Guard FastFlash® should be used for that application.

Q: Is Cat 5™ ICF suitable for below-grade or continuously submerged applications?
A: No. Cat 5™ ICF is not for use below grade or in locations designed to be continuously immersed in water.

Q: Does Cat 5™ ICF require a primer before application to common building substrates?
A: No. Cat 5™ ICF bonds to most common building materials without priming. Contaminated surfaces such as pressure-treated wood should be cleaned with an isopropyl alcohol wipe and allowed to flash off before application.

Q: Is Cat 5™ ICF appropriate for use behind rain screen cladding?
A: Yes. Cat 5™ ICF meets the requirements for pressure-equalized rain screen construction and is appropriate for use on exterior sheathing behind open-jointed or vented rain screen cladding systems.