# radiant floor heat



## Warmsmeallup (Apr 2, 2008)

BadgerBoilerMN said:


> professionals don't use bubble-foil.


Bubble..what? Do you mean the worthless stuff advertised for under concrete pours?



BadgerBoilerMN said:


> The more important issue is making the cavity below the radiant panels air-tight.


As I described....though 'air-tight' is unrealistic to obtain, the next layer down from the zmesh is a double faced foil (like Microfoil or foil faced insulation board) stapled to the side of the joists which is also a vapor barrier. This allows the element to heat the pocket of air created and reflect upward as well as downward. The fiberglass batting 1" down from the reflector adds to the total "R".


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