Blown insulation over batts w/foil barrier?
 

I have R-19 with a foil radiant barrier laying on top of the existing batts. I'm wanting to get to R-60 and looking at blown wool/fiberglass on top of that. Looks like HD carries the Owens Corning stuff called AttiCat which doesn't compress as much as cellulose, and I'd put down like a 12"-14" of that.

Any possible problems with moisture or otherwise since that barrier would be in between batts and blown? Or maybe I'm on to some new technique with this application? :)

You should really remove the foil barrier since it will act as a vapor barrier and help trap moisture in the existing batts.

Also, I'd still recommend cellulose over blown fiberglass. The advantages are numerous but top on my list is lower cost, using a mostly recycled product, and less variance in R value. The compression issue with cellulose IMO isn't a big deal at all. Just be sure to compensate for it by blowing in an extra inch or two.

I installed a breathing foil radiant barrier as you explained.
There are 2 types of foil radiant barrier, 1 is a vapor barrier, the other isn't.
Most likely what you have is breathing foil radiant barrier.(has small holes in it to breathe)
I can't see anyone putting a vapor barrier on top of insulation as it would steam up and rot underneath.

Yes, the foil has small holes in it. Ok, so I'm reading review where some people really talk about how much the cellulose really compresses. I also like the lower cost too, and I'm gonna go for like R-60+ anyway, so maybe like 12-14" of it.

Blowing cellulose over fiberglass is a bad idea if you don't want mice in your house. Mice love fiberglass for some reason. They don't really like cellulose though. So if you put R 41 of cellulose on top of fiberglass you are effectively creating a very warm and cozy space for them to bed down. In my experience this ALWAYS happens. I have never seen an exception. No amount of cats in a house will keep them out in the winter. And I also highly recommend cellulose. Forget cost. It's better for any other number of reasons. The only, ONLY, benefit I see to other forms of insulation is that the foams have a higher R value. Cellulose has so many perks that there is literally thousands of pages written about it.

Also, how do you keep it away from air exchange handler and other such equipment in attic? How do you keep it from "falling into" such equipment? I'm thinking of making some cardboard walls around it where it could topple...thoughts?

That's a simple one. Just put that stuff somewhere in conditioned space where it belongs and you're all set ;)


Wait... your air handler is in the attic? Just wrap that stuff in FSK, like the code requires,

Uh, I dunno what FSK is?

Just to be clear, since I may not be calling it the correct name, the fan that blows the cold air is my attic, so that's what I called the air handler, is that correct? My furnace (LP), is also up there in the attic too.

Yeah the air handler is the thing that has the fan. FSK is a duct insulation. It's nasty. It's a foil faced, treated fiberglass. It smells like all the fury of hell. There are special ways to apply it so it can maintain its R value along the entire circumference of the duct.

Don't put insulation on the furnace........ Just in case you were thinking I meant that too.

S-F thanks for your help! So, my plan was "mastic the hell" :) outta the metal duct work. My supply tubes that distribute the air are pretty good. I had got up there a few yrs. ago and zip-tied everything back together, but I got spots where the outter plastic wrap has just fallen off.

Can I just take that FSK stuff and wrap it in those spots where the plastic came off, and on a few of the places where it splits?