Continuous insulation (CI) is required by today’s energy codes to improve thermal performance. This article covers key materials, installation methods, and tested systems that reduce heat loss through the building envelope.
Overview
Continuous insulation refers to insulation installed without thermal bridges across all structural members, except fasteners and service openings. It significantly reduces thermal bridging and helps buildings meet or exceed code requirements such as those found in ASHRAE 90.1 and the IECC. This article explores insulation types, wall systems, and products that support effective CI use.
Types of CI Materials
- Polyisocyanurate (Polyiso): High R-value per inch, foil-faced for vapor control
- Extruded Polystyrene (XPS): Durable and moisture-resistant, ideal for below-grade and exterior walls
- Mineral Wool Board: Fire-resistant and vapor-permeable, used with rainscreens
- Spray Foam (Closed Cell): Can provide CI in some assemblies if applied in correct thickness
Installation Tips
- Stagger joints and seal all seams with compatible tape or flashing
- Use mechanical attachment or furring systems for cladding
- Install drainage plane behind CI in rainscreen assemblies
- Follow manufacturer guidance for thermal performance and exposure
- Coordinate CI with air/vapor barrier detailing
🔍 Quick Picks
- Best Polyiso CI Board: Rmax Thermasheath-3 Polyiso Insulation
- Best CI-Compatible Tape: 3M All Weather Flashing Tape
- Best Mineral Wool CI: ROXUL Comfortboard 80
🛒 Product Highlights
- Rmax Thermasheath-3: Foil-faced polyiso board insulation that meets code-required CI R-values with high thermal efficiency.
- 3M Flashing Tape: Used to seal polyiso seams and improve air and moisture control in CI systems.
- ROXUL Comfortboard 80: Mineral wool CI board ideal for fire-rated and breathable wall assemblies in rainscreen walls.
🧱 Used In These Assemblies
- Exterior CI wall with fiber cement or metal panels
- Hybrid assemblies using sheathing + rigid CI + cladding
- Fire-rated wall systems for multifamily or mixed-use buildings
❓ FAQ
Does CI count toward R-value compliance?
Yes. CI significantly contributes to meeting required R-values and reducing overall U-factors in wall assemblies.
Can CI be installed over sheathing?
Absolutely. It’s commonly placed over sheathing with fasteners or z-girts for cladding support.
🛠️ Related Articles
- Continuous vs Cavity Insulation Explained
- Polyiso vs XPS vs Mineral Wool
- How to Detail CI Systems for Code Compliance
Conclusion
Continuous insulation is a required element of modern energy-efficient design. Select appropriate CI materials for your climate, wall type, and cladding, and ensure all seams are sealed for maximum effectiveness.
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