Is rFoil concrete barrier OK to use under concrete slab?
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Don't think it will do any harm but not sure how much good it will do. What is the R-rating for direct contact with concrete above and soil below? Compare it to x" of foam. Make your choice.
I installed the 1/2 inch foam with aluminum sandwiched in the middle under my garage radiant slab. I am quite impressed with it's ability to prevent heat transfer. I forget the manufacturer but it's dense, high quality material.
The beauty of anything foil faced is its ability to reflect radiant heat. Heat loss under a slab is solely by conduction, so the use of foil is negated.
Use at least 2" of foam. It might seem warm using "alternative" insulations, but they will cost you more to operate your building.
Most of these shiny insulations are or have been challenged by the Federal Trade Commission for mis-stating the performance of their materials.
And this is ongoing , even with the suits being brought forth since they are boinking the uniformed for so much money.
They are never certified by Factory Mutual, the insulation trade standard used by all bona fide insulation manufacturers.
Caveat Emptor! There is no free lunch when it comes to insulating slabs.
Use at least 2" of foam. It might seem warm using "alternative" insulations, but they will cost you more to operate your building.
Most of these shiny insulations are or have been challenged by the Federal Trade Commission for mis-stating the performance of their materials.
And this is ongoing , even with the suits being brought forth since they are boinking the uniformed for so much money.
They are never certified by Factory Mutual, the insulation trade standard used by all bona fide insulation manufacturers.
Caveat Emptor! There is no free lunch when it comes to insulating slabs.
I know of a house where the cellar radiant floor was done with foil bubble because a contractor substituted it without checking with anyone. The results are not awful, but the cellar zones almost never come on due to other heat escaping from the boiler (not a good sign either). Not my house, mine is older and more primitive...
I agree with others that foil type stuff is _maybe OK_ at reflecting radiant heat transfer, but that only works with an air or vacuum void between foil and the warm surface that it is supposed to reflect to. If you are putting in $ and time, spend the little bit extra to do it right. It will cost less in the long run, even if the cheaper and easier options might not fail in a quick or disastrous manner. I know this from experience from trying to solve various things over the years that predecessors in various places _did_ opt to try to do in the cheapest and easiest manners that anyone suggested. Even if you do not inherit the problem, why leave bad crap to people in the future? That outcome wastes resources, in the long run, too. I know, I am old fashioned.... but I am always glad, and sing praises to the people who came before, even if their names are unknown, when I work with things where someone did _not_ do it the cheap and easy way.
I agree with others that foil type stuff is _maybe OK_ at reflecting radiant heat transfer, but that only works with an air or vacuum void between foil and the warm surface that it is supposed to reflect to. If you are putting in $ and time, spend the little bit extra to do it right. It will cost less in the long run, even if the cheaper and easier options might not fail in a quick or disastrous manner. I know this from experience from trying to solve various things over the years that predecessors in various places _did_ opt to try to do in the cheapest and easiest manners that anyone suggested. Even if you do not inherit the problem, why leave bad crap to people in the future? That outcome wastes resources, in the long run, too. I know, I am old fashioned.... but I am always glad, and sing praises to the people who came before, even if their names are unknown, when I work with things where someone did _not_ do it the cheap and easy way.
It isn't just us saying this either - here is a nice article by Siegenthaler, arguably the top name in the hydronic world these days, talking about bubble wrap and other such snake-oil insulation materials... Answer his questions, then see if you still want to use the stuff...
http://www.pmmag.com/Articles/Column/ade39412e70d7010VgnVCM100000f932a8c0____
Gooserider
http://www.pmmag.com/Articles/Column/ade39412e70d7010VgnVCM100000f932a8c0____
Gooserider
Thanks once again for all the information. Like so many other newbies I really appreciate this site. As I have said before, we want to do things right the first time.
when all the air bubbles finally break, as many do when you walk on bubble foil, you now have an expensive vapor barrier, nothing more.
stick with extruded foam board listed and tested for underslab use. 2" is best. more important is the edge detail, that is the highest loss area in a slab on grade job. 2" at least there with a means to protect it against the elements, maybe a custom flashing.
hr
stick with extruded foam board listed and tested for underslab use. 2" is best. more important is the edge detail, that is the highest loss area in a slab on grade job. 2" at least there with a means to protect it against the elements, maybe a custom flashing.
hr
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