I had a shed delivered to use as a hobby shop and plan on climate controlling it, so I was going to install batt insulation. I told the shed guys this and they talked me into getting the silver treatment, which is the radiant barrier OSB roof and wall sheathing. But when I went in the shed, printed on the silver side it says “for open wall use only.” Is there a way to add batt insulation with this?
Answer
Radiant barrier material like foil-faced OSB are effective in reducing radiative heat flow when there is an air space next to the foil (the silver-colored surface). The effectiveness of the radiant barrier depends on the distance across the air gap. When the radiant barrier material is installed as roof sheathing, the air space is typically a few feet in depth.
If you decide to add fiberglass to the enclosure of the shed, then provide some space between the foil surface and the insulation – at least an inch of space. For the roof areas, a wider space (3-4 inches) would have benefit, especially in the summer. No damage will occur if you install insulation against the foil surface, but there will be no benefit from the foil.