That makes sense for it's typical application - under siding or roofing materials. As far as painting right over the panels goes, materials are heated by sunlight when they absorb infrared radiation. Shiny or bright materials reflect that IR away and thus absorb less of it. If you painted the foil on these sheets, the paint would invariably absorb more heat than the foil and that heat would be transferred to the foil and quite efficiently too as metals absorb heat rapidly That must be where the airspace comes in, preventing the transfer of heat between the outer layer and the foil. I will do a test tomorrow with a couple scraps of tuff-r I have as I'd love to paint my yurt too if the effect of the paint is negligible or marginal. I will paint stripes of different colors, using different types of paints (latex, acrylic), let them sit in the sun and take surface temperature measurements. I'll post my results.jkisha wrote:I did a quick Google search and found this article--there was a paragraph that caused me to believe that it wasn't important if the foil were covered, but it did need a bit of air-space in order to be effective. If I were in the construction business I think I'd call the manufacturer and ask directly; since I'm not, here's the link I found with the minimal info: http://www.ornl.gov/sci/roofs+walls/radiant/index.htmlHeironymousJosch wrote:I asked my local supplier the exact same question and he didn't have a very good answer. Beats me!jkisha wrote:Makes sense that the reflective surface would help keep the yurt cool; but I don't understand why in the world the company would have designed them to left exposed. Other than the hexayurt, when are they ever left exposed in construction?????