Hi,

I just finished ripping out the drywall on the inside of an exterior wall in my house.  We have been having issues with condensation forming on the inside of the wall when it gets cold.  I had had my house insulated using blown in cellulose about 10 years ago but clearly they missed some cavities.  Wherever they missed a spot due to weird cross bracing (and it turns out there were a fair few spots) we have been getting mildew.

Now that I have pulled off the drywall, I intend to do a “cross hatch” wall (or mooney wall). I am hoping the extra insulation (and, really, just having any insulation at all in the mildewy sections) will stop this condensation problem.

But before I do, it turns out that the existing cellulose (where it existed) has stayed in place quite nicely during my demo.  I’d like to just put up some insulweb type netting to hold it in place (and then add more dense pack in the empty cavities and those few cavities where the existing cellulose does not come completely to the top).  

I want to do this BEFORE adding the cross hatching since the installation of the new framing members will no doubtedly disturb the exisitng insulation to the point that it will fall out and I will have to start from scratch.  Once it is properly netted, I will add the cross hatched framing, and then most likely insulate within these new cavities using some rigid foam insulation.

So, my question:

What kind of netting (or material) can I use to hold the existing insulation in place?  Insulweb is what I keep seeing all over the internet, but I cannot seem to find ANY local stores that stock it.  Not the smaller lumber yards in my area (Redacted to get around spam filter) nor any of the big box stores.

Is there someplace I can source it around here?

Is there some other material that is safe to use inside my walls?  I saw a post here that suggested using landscaping fabric.  Is it ok to have that in the walls?

Should I try to carefully attach the new framing with screws (instead of nails) and hope that the vibrations don’t disturb the existing insulation too much and then use the rigid foam as a barrier against which I can then do my little bit of additional dense packing?

Or should I just forget about saving the existing insulation (it covers about 75 – 80% of the cavities) put up the new framing, and then try to blow in some dense pack.  My biggest concern with this methid is that I may not be able to get my hands on a blower that is capable of the 3.5-4 ilbs per square inch. This is the primary reason I am considering rigid foam for the additional thickness created by the cross hatching/mooney wall.

All suggestions greatly appreciated!