[luci468]

We're finishing our attic space and want to insulate it really well.
I want to use a radiant barrier like Reflectix but am concerned about using it with faced insulation. If I have kraft-faced insulation and then put the radiant barrier on top of it will there be an issue with moisture?
Also, I'm thinking of putting rigid foam panels on the crawl-space side of the knee walls and adding a radiant barrier to that (I've seen it mentioned in a few places) but that means sandwiching the insulation between the kraft facing and the foam panels/radiant barrier. How about a moisture issue here?
Thanks for your help.

 

[swatsell]

Barrier with insulation

Well, it's been a while since this was posted and I just joined today. In case you haven't found your answer yet, here's what I suggest.

The radiant barrier, I assume, is on the opposite side of the rafters from the roof and not next to the ceiling?

The radiant barrier will reflect heat that is radiating down from the roof. The heat trapped between these 2 will rise, assuming you don't have insulation between

With vents along the perimeter of your home under the eaves, cool air will enter. The heat between the roof and radiant barrier will cause an updraft to your vents at the top drawing this cool air through with it.

Bottom line, I think you need the air flow and believe the insulation would just be an extra cost to you. BTW, yes, it seems like the air would condense out in the insulation and cause a moisture problem.

Hope this helps,
Jerry