Posted By Blueridge company on 02/05/2009 9:22 PM
In my personal home where the radiant as 1 1/2 light weight on platform I have crawl space 18 inches over dirt I have 2x10 joist, stuffed with insulation. I blanketed from the underside 4 foot foil bubble foil. I suppose it adds to the overall performance of the building, I know when I work under the house I do not have a head full of fiberglass insulation, spiders and mice. Sooo... my point, these products are relatively inexpensive and have a lot of applications,
It just might add to the ability to enhance the 2 inch rigid foam........ A foam enhancement product.
But, I have no science. I might sugest we create a test, perhaps using an electric coil as heat source and several modles.
Dan
I'd hazard that in Vashon , whether the crawl space is ventilated or not the cold side of your fiberglass is gonna be well below the dew point for a good portion of the year. Putting the bubble-pack on the bottom side has a very
HIGH chance of developing a condensation, mold, & fungus issues on your joists. In New England that stackup is a disaster over a crawlspace. (Read your private messages.)
Vapor retarders only belong on the predominantly warm side of the insulation for the climate zone -
always. Class-I vapor retarders like poly sheeting & bubble pack only more so.