I am starting this thread over since I asked a question on someone else's thread.

My existing situation is I have a tri level home. The crawl covers the first two floors (first floor being between 2-4 ft high, the 2nd floor between 8-9 ft high. The existing insulation is unfaced R-11, so the floors and family room downstaris are very cold in the winter. I want to upgrade the insulation to R-25. My question is can I get R-19 unfaced and install under the existing insulation or should I start over with R-25 faced? If I should start over, what should I do with the old insulation? It's dry as a bone. Could I put that under the new R-25, put it in the attic (attic seems to be fine but more never hurts) or just sell on craigslist or throw away? Thanks for any help.

Yes you should be able to get an R-19 (or there abouts) and add to the existing insulation. You could probably use R-25 since the wires holding it up should not crush the R-25.

So, it's not a problem to have unfaced against the floor? I've always heard you should have faced so you have the vapor barrier, but obviously it would be cheaper for me to get the R-19 unfaced if that would do the trick and get me to at least R-25.

Well, that's what you have now, correct. There is not going to be much air movement through the subfflooring with the finished flooring on top. As explained in the other post it's the mixing of air masses that causes the condensation. Just didn't want you to trap moisture between two barriers.

OK, thanks. I know this is a dumb question, but I'll clarify anyway, I want to take the wire hangers off the existing, put the new stuff under the existing, then put the wire hangers back up, right?

I thought about that also, thinking that to existing insulation might fall in you face. Then I thought why remove the hangers, just leave them in place and use additional ones for the new.

Wouldn't that cause air pockets between the 2?

Maybe, but that's what insulations does, trap air. That air trapped in between the fibers is what gives it it's insulating qualities.