Does a radiant barrier affect my roof?

Radiant barriers are being installed in residential attics with great results, but you may hear some in the building industry advise against this practice.

If you are concerned with reducing your utility bills, you will know about radiant barriers. Reducing the heat in your attic during the hot summer months, can be crucial to maintaining a cool home. Suggestions to reduce the heat coming through your roof have included painting roofs white, or using new roof covering materials that prevent the heat from coming through. If you do not want a white roof, or you do not wish to buy a new roof, installing a radiant barrier is a cost effective solution.

There is a concern with this foil insulation that some in the building industry are stating. The concern revolves around the principle of how a radiant barrier works. The sun's rays heat up your home with its energy. The radiant barrier reflects the rays which produce the heat in your home. If these rays are passing through the roof, and then being reflected back through the roof, the heating of the roof material happens twice. Heat a material up, and you can see it break down from this heat. This process causes the issue with radiant barriers for some. However, let us consider what happens without the radiant barrier. The sun's rays pass through the roofing material, heating up the attic. This heat is contained in the framing and air of the attic. During the day, the heat dissipates into our living spaces, but at night, the heat goes back through the roofing material. Not as much as with a radiant barrier, but still we are heating the material twice, so either way, we are breaking the roof covering down.

Does this cause my roof to not last as long? We really do not know. There are several factors which go into determining the life expectancy of your roof. Composite shingles and other roof covering types do contain protection from these sun's rays. This protection can be effected by the weather and other factors. Quality of the installation and the materials plays its part. Ventilation of the attic space, particularly under the roof, is also a key component to determining roof life. So far, we do not have enough data that the extra heating from a radiant barrier does break down the roof material. At this time, the life cycle of the roof appears to be the same. We do have data that radiant barriers do cool the attic, which in turn is better for the living spaces below.

We often do not think about our roofs, until we have a leak. Considering that so many factors could affect the life, a radiant barrier is not adding that much more stress to the roof material. With proven benefits in reducing heat, a radiant barrier is a good addition in a strategy to lower energy usage.

Photo credits : swisscan and .jowo. of Flickr