The Effect of Radiant Barrier on Roofing

Types of Radiant Barriers

• Radiant barriers come in a variety of shapes and sizes, but reflective foil is by far the most common. Reflective foil consists of one or more layers of aluminum applied to a facing material such as kraft paper, cardboard or plastic. Other radiant barriers currently available include reflective metal shingles, laminated roof sheathing and reflective chips that can be applied to the surface of loose-fill insulation.

Effects of Radiant Barriers on Roofing

• Radiant barriers have been shown to increase the heat of the roof surface directly above them. This is a natural side effect of the barriers' function as a guardian of the attic below. Heat has nowhere to go but back to the roof above. Tests have proven that radiant barriers increase roof temperatures by 2 to 10 degrees Fahrenheit on sunny days.

Controversy

• No one doubts that radiant barriers heat roofing systems. The controversy is whether or not this additional heat causes damage to materials and results in a shorter roof life. Roofing manufacturers are divided on this issue, some refusing to warranty roofing that has had a radiant barrier installed below it. Others do not have this exclusion. As of 2011, radiant barriers have not been in use long enough to be able to determine the effect of their prolonged use with roofing material.

Special Applications

• Radiant barriers are valuable for structures like uninsulated barns with metal roofing and siding. Their ability to reflect heat back toward the roof keeps these uninsulated spaces cooler without affecting airflow. This is invaluable during hot, muggy summers where valuable equipment or animals are housed. Because the radiant barrier is installed near the roofing, it is protected against most kinds of accidental damage.