Perforated vs Non-Perforated Radiant Barrier
The right radiant barrier is not simply the one with the highest advertised number. The important first decision is whether the building assembly should allow vapor to pass through the material or intentionally block it.
Laser Perforated (LP) vs Vapor Barrier (VB)
| Decision point | Laser Perforated (LP) | Vapor Barrier (VB) |
|---|---|---|
| Vapor behavior | Micro-perforations allow water vapor to pass through the sheet. | Non-perforated material is intended to restrict vapor transmission. |
| Common uses | Vented attics, roof rafters, attic floors, cathedral ceilings, and other breathable assemblies. | Assemblies intentionally designed for vapor control, radon control, or a sealed reflective layer. |
| Safer default | Yes, for most typical residential attic projects. | No. Use it when the assembly specifically calls for a vapor barrier. |
| Installation planning | Preserve ventilation paths and maintain an adjacent air space at a reflective face. | Coordinate seams, penetrations, and placement with the complete vapor-control design. |
When to choose Laser Perforated (LP)
Choose Laser Perforated material when you need radiant-heat control without turning the radiant barrier into a non-perforated vapor barrier. This is usually the better fit beneath existing attic rafters, over attic-floor insulation, and in other vented assemblies.
- Recommended for most vented residential attics.
- Available in widths suited to 16-inch and 24-inch on-center framing.
- Double-sided reflective construction makes either face available to the adjacent air space.
- Perforations help the assembly continue to dry as designed.
When to choose Vapor Barrier (VB)
Choose Vapor Barrier material only when restricting vapor is part of the project design. Climate, material order, air conditioning, moisture sources, and local code all affect where a vapor barrier belongs.
- Non-perforated for intentional vapor-control applications.
- Can be used as part of selected radon-control assemblies.
- Seams and penetrations may need to be sealed when continuity is required.
- For walls, floors, and enclosed roof assemblies, confirm placement before installation.
Why oxidation protection matters
Bare aluminum exposed to attic heat and moisture can develop a surface oxide layer that reduces long-term reflective performance. Ra-flect uses coated aluminum selected to resist oxidation and maintain 95% reflectivity over time. A 97% reflectivity claim by itself does not establish long-term attic performance.
Reflectivity is not a fire classification
Reflectivity, flame spread, and smoke development are separate properties. Where a Class A or Class 1 classification is required, review current ASTM E84 test documentation using the mounting method applicable to the product and project, including ASTM E2599 where required. Do not rely on a reflectivity percentage or an outdated test report as proof of code compliance.
Still deciding? Review the installation methods first, or request a free Laser Perforated sample to inspect the material before ordering.
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Laser Perforated (LP) is the safer default for most vented attics and breathable assemblies. Choose Vapor Barrier (VB) only when non-perforated vapor control is an intentional part of the design.