R-Guard Cat 5 Rain Screen Air & Water Barrier Membrane - 5 Gallon

R-Guard Cat 5 Rain Screen — Fluid-Applied Air & Water Barrier for Pressure-Equalized Rain Screen Construction

R-Guard Cat 5 Rain Screen is a single-component, fluid-applied waterproofing and air and water barrier membrane engineered specifically for pressure-equalized rain screen construction. Formulated with a silyl-terminated polymer (STP) chemistry that combines the best properties of silicone and polyurethane, it delivers a seamless, elastomeric, weatherproof membrane on exterior sheathing behind open-jointed or vented rain screen cladding. Designed for contractors who need a reliable, high-performance building envelope solution, Cat 5 Rain Screen is proven to withstand conditions ranging from everyday weather to the drenching rains and 155-mph winds of a Category 5 hurricane.

Unlike traditional sheet-applied membranes, Cat 5 Rain Screen is fluid-applied by sprayer or roller, eliminating seams and laps that can become failure points. Its STP chemistry sets it apart from pure silicone or polyurethane alternatives by delivering the durability and flexibility of both chemistries in a single, easy-to-apply product that adheres to most surfaces and is immediately waterproof upon application.

Key Features & Benefits

Seamless, Elastomeric Membrane

The fluid-applied process creates a continuous, seamless membrane across exterior sheathing with no laps, seams, or mechanical fasteners. This elastomeric membrane flexes with the building substrate, maintaining a weatherproof seal under dynamic conditions.

Category 5 Hurricane-Proven Wind and Water Resistance

Cat 5 Rain Screen is proven to prevent water and air penetration of the building envelope in conditions up to 155-mph winds, equivalent to a Category 5 hurricane. Contractors working in high-wind or coastal zones can specify this product with confidence in its performance envelope.

Application to Dry or Damp Substrates

Cat 5 Rain Screen can be applied in unfavorable weather conditions to both dry and damp substrates. This capability eliminates many weather-related construction delays and accelerates the drying-in of new buildings, keeping projects on schedule.

Immediately Waterproof Upon Application

The membrane is immediately waterproof as soon as it is applied, providing protection to the building envelope without a required cure window before rain exposure. This is a critical advantage during fast-moving construction schedules.

Single-Component STP Chemistry

The single-component silyl-terminated polymer formulation requires no mixing, reducing the potential for application errors on the jobsite. STP chemistry delivers a highly durable, flexible membrane that combines the best attributes of silicone and polyurethane technologies.

Broad Compatibility

Cat 5 Rain Screen is compatible with most sealants, waterproofing products, and air barrier components, as well as adhering to most surfaces. This makes it straightforward to integrate into complex wall assemblies without concerns about chemical incompatibility.

Living Building Challenge Red List Reviewed

R-Guard Cat 5 Rain Screen has been reviewed by PROSOCO for conformance with Living Building Challenge 2.1/2.2/3.0/3.1/4.0 Materials Petal Red Lists and is confirmed to not contain intentionally added chemicals present on the Red List. It also complies with all known Living Building Challenge, LEED 2009, and LEEDv4 referenced architectural coating and sealant regulations, including CARB 2007 SCM, SCAQMD Rule 1113, and SCAQMD Rule 1168.

Common Applications

Pressure-Equalized Rain Screen Wall Systems

Cat 5 Rain Screen is specially formulated to meet the unique requirements of pressure-equalized rain screen construction, serving as the primary air and water barrier membrane behind open-jointed or vented cladding systems.

Exterior Sheathing Protection

Applied directly to exterior sheathing, the membrane forms a durable, weatherproof layer that protects the building structure from water infiltration and air leakage before and after cladding installation.

High-Wind and Coastal Construction

Proven performance in conditions up to 155-mph winds makes Cat 5 Rain Screen appropriate for projects in hurricane-prone, coastal, or other high-wind-exposure environments.

Fast-Track and All-Weather Construction

The ability to apply to damp substrates and achieve immediate waterproofing makes Cat 5 Rain Screen well suited to accelerated construction schedules where weather delays must be minimized and buildings need to be dried in quickly.

Compatible Materials

• Most exterior sheathing substrates (dry or damp)
• Most sealants
• Most waterproofing components
• Most air barrier components
• Most surfaces (per manufacturer's general adhesion statement)

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
• NFPA 285 Compliant Wall Assemblies
• LEED Verification Letter
• SCS Certification
• LBC Red List Conformant Product Summary
• LEED Verification Letter (Updated)
• LBC Red List Conformant Product Summary (Updated)
• ICC-ES Evaluation Report ESR-3416
• SCS Certification (2022)
• Product Test Data (Updated)

Technical Specifications

Frequently Asked Questions

Q: Can Cat 5 Rain Screen be applied in wet or cold weather conditions?
A: Yes. Cat 5 Rain Screen is formulated for application in unfavorable weather conditions to dry or damp substrates, which helps eliminate weather-related construction delays and accelerates the drying-in process on new buildings.

Q: Is Cat 5 Rain Screen suitable for high-wind coastal projects?
A: Yes. The product is proven to prevent water and air penetration of the building envelope in conditions up to 155-mph winds, equivalent to a Category 5 hurricane, making it appropriate for demanding coastal and high-wind-exposure applications.

Q: Does Cat 5 Rain Screen require mixing before application?
A: No. Cat 5 Rain Screen is a single-component product, meaning no mixing is required. It can be applied directly from the container by sprayer or roller.

Q: Is Cat 5 Rain Screen compliant with green building standards?
A: Yes. PROSOCO has reviewed Cat 5 Rain Screen for conformance with Living Building Challenge Red Lists (versions 2.1 through 4.0) and confirmed it does not contain intentionally added Red List chemicals. It also complies with LEED 2009, LEEDv4, CARB 2007 SCM, SCAQMD Rule 1113, and SCAQMD Rule 1168.

Q: What is the difference between Cat 5 Rain Screen and a standard fluid-applied air barrier?
A: Cat 5 Rain Screen is specifically formulated for pressure-equalized rain screen construction behind open-jointed or vented cladding systems. Its STP chemistry combines the best properties of silicone and polyurethane, and it is proven to perform under Category 5 hurricane-level wind and rain conditions.