Perforated Radiant Barrier (vs. Non-Perforated Solid Vapor Barrier)

When installing a radiant barrier over the attic floor, over existing insulation in place or not, you MUST use a perforated radiant barrier.  This is because moisture-laden air generated in your home from breathing, washing clothes, bathing, running the dishwasher, etc travels upwards and must be able to pass through the radiant barrier to escape your attic.  If a solid radiant barrier were used in this location, it would trap the moisture in the air and condensate resulting in water droplets that would drip onto your insulation/attic floor and rafters causing damage.

Our RadiantGUARD® Ultima also comes in a non-perforated solid version.  Our RadiantGUARD® bubble insulation products are only available in a non-perforated solid version.  Non-perforated solid products serve as vapor barriers.

When MUST you use a non-perforated (SOLID) radiant barrier?:

If you are using a radiant barrier in wall cavities as a house wrap you MUST use a non-perforated (SOLID) radiant barrier:

• IF you live in high humidity / high hydrostatic pressure areas located between the southern tip of Texas and the Florida-Georgia border on the Atlantic Ocean AND you have a stucco structure,

• OR you are installing in sub grade locations in any area of the country (basements/underground rooms),

• OR you are installing a radiant barrier in a cathedral ceiling application between the insulation and the ceiling drywall.

For more information regarding vapor barriers, please visit the following websites:

• Vapor Barriers - DOE

• Insulation Vapor Barriers