An oxygen ion has a -2 chargeHow many protons and electrons does the oxygen ion have?and An aluminum ion has a +3 chargeHow many protons and electrons does the aluminum ion have?
An oxygen ion has 8 protons and 10 electrons ( -2 charge) An aluminum ion has 13 protons and 10 electrons (+3 charge)
If there is room for more insulation then you can add itThe Kraft paper would need to remain on the inside against the drywallIt would be easier and neater to just throw out the old insulation and put in new kraft faced battsThe cost difference would not be that much If you did just add to the existing you would have to pull down the existing and install unfaced batts insulation and then re-installed the old kraft face batts over them The kraft paper is an important vapor barrier.
the folks saying not to add insulation are correctIt compresses the existing and then you're wasting moneyIf you want to get better than R-13 or so, add a aluminum/foil bubble layerSold at most hardware stores, under names like reflectix, etcVery efficient, adds between 2 and 6 to R valueAnd replace the old stuff while you're in there.
depending on the design/age/construction of your home, you could pull out the insulation (CAREFULLY and SAVE IT) and use spray foam or caulking to seal ALL openings to the outsideand put the insulation back and improve your vapor/moisture/wind barrierdepending on construction, if the contractor (or home builder) didnt use much for vapor barrier, this will help more than anythingin a properly sheathed wall, R-13 or 15 insulation will work FINE, as long as AIR cannot get thru that easily
I ran into a similar problem with one of my customers hearing water running down pvc pipe when upstairs toilet was flushed, the insulation in the wall was ok but not to sound proof so I removed it all out and installed a good rated insulation for that purposeMy customers loved the job and have been using me for over 8 years nowMy specialty is plumbing but that worked fine.
