3/4" 4x8 POLYISO FOIL SHEET R5.0
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Elevate your building's thermal performance with our 3/4" 4x8 Polyiso Foil-Faced Insulation Board. Engineered for maximum efficiency in a slim profile, this rigid foam board is the gold standard for moisture resistance and heat reflection.
Product Overview
This Polyisocyanurate (Polyiso) sheet features a high-density closed-cell foam core sandwiched between two heat-reflective aluminum foil facers. At only 3/4" thick, it provides an impressive R-5.0 thermal resistance, making it ideal for tight spaces where traditional insulation won't fit.
(Note: While the "R-13" in your search often refers to a total wall system R-value when combined with other materials, this specific 3/4" board provides a standalone R-5.0.)
Key Features
Superior Thermal Reflection: The radiant barrier foil facers reflect up to 97% of radiant heat, keeping interiors cool in summer and warm in winter.
Moisture & Vapor Barrier: Naturally water-resistant, it prevents moisture buildup and protects against mold and mildew when joints are properly sealed.
Space-Saving Design: Delivers higher R-value per inch compared to fiberglass, XPS, or EPS foam.
Easy Installation: Lightweight and easy to cut with a simple utility knife. The 4x8 dimensions are standard for seamless integration with studs and joists.
Specifications
| Feature | Details |
|---|---|
| Dimensions | 3/4" x 4' x 8' |
| Material | Closed-cell Polyisocyanurate |
| R-Value | R-5.0 (at 75°F) |
| Facing | Dual-sided Reflective Aluminum Foil |
| Edge Profile | Square Edge |
| Fire Rating | Class A (standard for most building codes) |
Common Applications
Interior Walls: Perfect for basement finishing or masonry wall furring.
Attics & Crawlspaces: High-performance thermal break for joists.
Ceilings: Increases energy efficiency in garages or workshops.
Specialty Projects: Used in vans/RV conversions and custom sheds.
Pro Tip: To achieve the highest energy efficiency, use high-quality foil tape to seal all seams and joints, creating a continuous air and vapor barrier.