non foil faced boards

[crispy_wafer]

Just browsing a 2nd's site for insulation, I notice they sell non foil faced PIR boards...  What's the use case for these?  If they came up in the sizes I needed could I use these as floor insulation? 

[Cpd]

I think the answer is yes ! The foil is to help performance but only works if there is a gap between the foil face and the next surface so buried in a floor build up should be fine. 
maybe wait until someone confirms this before buying ?

[Oz07]

Isn't foil like a vcl? Does it actually help the insulation?

[SteamyTea]

Read up about it here.

https://en.wikipedia.org/wiki/Thermal_radiation

 

The calculate that it isn't worth the bother as the temperature differences are too small.

 

Thinking about it as visible light is not how it works, we can't see sound and radio waves, but we can reflect, bend and focus them.

The smaller the gap between the radiative and adsorption surfaced the more energy transferred. Conduction is only radiative transfer, but at the scale of electrons turning into photons.

 

Edited June 21, 2021 by SteamyTea