i just picked some up. they gave me some 4" thermax that had been sitting in their warehouse for the same prices as 1.5". Still spendy, but kinda excited about the r-value. I haven't installed it or painted it, but the internet seems to indicate you can paint it.

Here is a link that might be useful: Thermax Painting

Sgclarke & chillcox, hope you are still around, did you use it? Any problems? Are you happy with the results? Anyone else - thoughts?

It's typically used in commercial, especially agricultural structures, as it can withstand 1,000 psi pressure-washing at three feet. Something that most people aren't likely to be doing in their rec room.

Thank you worthy for responding. I am thinking of using it because it can be left exposed. I have no interest in framing and putting drywall up in my basement.

Hi! We did put it up around half the basement and immediately noticed that the basement was cozier. Pulled back from walls recently and aaw no mildew.

It depends on where/how you use it. The R-value per inch is a little better than XPS/EPS and possibly even CC-SPF. The foil-faced stuff qualifies as a fire barier in many locales (so you don't have to cover it with drywall, for example). Be careful about using it in any environment that can be damp (i.e. basements). If so leave the bottom edge unsealed or sealed with a water-permeable sealant. The foil is a functional vapor barrier but the foam in the panels is NOT vapor-impermeable like XPS and it'll wick like a sponge if left damp (or if you puncture the foil accidentally, etc). I personally use it to put a fire-rated cap on the foam blocking against my rim joists since I leave them exposed in some places. If you're using it in a space which has no moisture risks, it insulates like a champ.