We are planning to use a radiant barrier in a new construction. It mentions in your (RIMA) manual for installation to use furring strips to separate the outer skin from the internal structural wall. I am guessing that this means: sheet rock, fiberglass or some type of insulation, the radiant barrier, furring strips followed by the exterior siding. The main question is, do the furring strips act as a thermal break or is there a product that should be used on the studs to avoid heat transfer through the wooden studs?
Answer
The furring strips will provide a minimal thermal break — perhaps less than an R-1, but will mostly be a conductive heat path. The radiant barrier will be a direct conductor of heat wherever it is in contact with another surface. Still, the vast majority of the radiant barrier will be facing an air space in the system you describe, and that’s good. If there is also a way to provide ventilation to the airspace that faces the radiant barrier, that would be even better. Otherwise, it won’t take all that long for the airspace to reach a steady state temp that would allow the heat from the siding to pass through and begin its transfer to the living space. The optimum airspace is 3/4”. Hope this helps.