Foil against the sheetrock?
dennisyurcik
| Posted in Energy, Heating & Insulation on
I’m midway through some attic insulation upgrades and someone just mentioned to me that “people” were using foil in the attic to reflect heat back into the house. Unfortunately, I don’t have any details and I’m left with lots of questions. I’m hoping you all can help me. So here goes:
1) Did he mean foil backed foam? Or something else?
2) If foam, do I cut it to fit between the joists and lay it against the sheetrock ceiling?
3) Will the foil trap moisture an lead to mold?
4) Is it even worth the trouble/cost?
Right now I have typical 16″ wide fiberglass batts running between the joists. I was just going to blow in more insulation over top of the batts.
Thanks for your help.
-Dennis
Replies
Go over to
Green Building Advisor, search for the blog posts on radiant barriers, and read up.
Move all that fiberglass around and air-seal your attic floor before you do anything else.
Air sealing is complete.
Yes, the air sealing is complete. Did that dirty work already. Was just about to deal with blowing in the insulation, but now I'm wondering is it worth putting that on hold and adding foil first.
I'll do some reading on radiant barriers. Thanks for the tip.
From what I have read
the only possible real use for foil is as a factory-installed facing on the roof sheathing (faces down)... and I guess in some places people staple it across the bottoms of the rafters. Idea is to reduce heat into the attic in hot/sunny areas, especially with ductwork in there. If you have no ductwork in the attic, just insulate the heck outta the floor and don't worry about the attic temp at all. Another source of info is Florida Solar Energy Center... FSEC.