You may have heard that a radiant barrier can’t go under a shingled roof because there is no air gap between the deck and the shingles. While that is true, if you are building NEW construction, you can easily get radiant barrier under the roof and have results that works almost 20% better than traditional radiant barrier decking like TechShield™ or Solarboard™!

The method shown in the photo above shows how you can add a radiant barrier below a shingle roof on new construction. This method is similar to radiant barrier decking (like Solarboard® and Techshield®) but the difference is that this method utilizes a draping of the foil, so that air exists on BOTH sides of the radiant barrier. Why is that better/more effective?

When air is between the deck and the foil, the foil uses REFLECTIVITY to block heat transfer rather than emissivity. When the foil is directly against the deck (like Solarboard® or Techshield®) the foil uses the air space below it (in the attic) to block heat transfer via EMISSIVITY.

Test results of installations where the foil uses reflectivity vs emissivity have shown that there is a greater reduction of the overall heat gain when aluminum reflects heat away. This also keeps the decking cooler, which is better for the life of the roof. If you’re in new construction or re-doing the decking on your existing roof, this is a great option to consider for adding radiant barrier foil to your roof.