Metal roofing that uses battens or has a naturally occurring air space makes adding a radiant barrier very simple. The main goal is to get the foil down first, before the battens, then install the batten system on top of the foil and continue as normal.

The air gap that is created by the battens allows the foil to work as a radiant barrier that will use REFLECTIVITY to block heat coming off the roof from passing through the foil and in to the area below the foil. The air gap should be ½" of air or more. The larger the air gap, the better your roof can ventilate but the foil will work the same whether your air gap is ½" or 1 foot. Your result is 97% of radiant heat is blocked and the structure (whether a home or a commercial building) is cooler inside.

We recommend attaching the RoofingFoil™ + Underlayment to the deck with plastic cap roofing nails. You can use staples if you don't have access to the plastic cap nails, but they're not preferred. Remember to overlap your RoofingFoil™ + Underlayment at least 4" (up to 6") all the way up the roof for best results. 

With a batten system, the layering of the roof looks like this (coming from the roof down toward the interior of the building):

  • Metal roof
  • Batten system
  • ½" minimum air gap created by battens
  • Foil
  • Deck (or existing shingle roof)
  • Etc.

If the metal roof will be placed directly on top of framing, with no decking or battens, then the foil can be placed directly over the framing before the metal. You can use staples to attach the foil to the frame if it is wood but for the best water-tight seal we recommend you use the plastic cap roofing nails. If it is a metal frame, both screws and double-sided adhesive tape work for holding the foil in place until the metal is attached.

Without a deck (and no battens), the layering of the roof looks like this (coming from the roof down toward the interior of the building):

  • Metal roof
  • Foil attached to framing
  • ½" minimum air space created by framing (ie. nothing below the foil toward the interior)
  • Attic/ interior
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