what's the best way to run foil on R+ EPS 2" insulation

[DeCorps]

I'm adding R+ EPS 2" insulation over existing sheetrock and R-15 to achieve R-21, I am not sure the best way to run the foil, inside gives a small gap, outside will glue directly to the sheetrock. Should I space it or just glue?

 

[ShieldHero]

The foil does provide a small benefit as a radiant barrier, but it's only effective if there's a gap of at least half an inch to three-quarters of an inch between it and the surface. That's the crucial part when you're setting up the sheets

 

[Maguire]

I'd recommend spacing the foil slightly for better air circulation and reflective efficiency, gluing directly can reduce performance, a small air gap helps maximize insulation and moisture control

 

[fenharxz]

Thanks, I'm understanding.

 

[Equalizer1]

I'm adding R+ EPS 2" insulation over existing sheetrock and R-15 to achieve R-21, I am not sure the best way to run the foil, inside gives a small gap, outside will glue directly to the sheetrock. Should I space it or just glue?

What are you working on, walls or ceiling? Is it interior or exterior?