Basement insulation

Two story 4 plex from 1950's. Upstairs apt. 12 x 50 foot apt., approx. 220 electric baseboard heat in building. Wall crack in the plaster above 8' electric baseboard heater on outside living room wall that faces west. And plaster bulging to point it has to be removed/redone. But no discoloration. Wall makeup: Inside 1/2 inch real plaster, 1/2 celotex-like fiber board or 'cornboard' the plaster was applied to, 3 1/2 inch thick wall cavity with studs every 16 inches, blown in insulation completely filled cavity (the type that looks like whitish fuzzballs from a sweater), celotex up against the outside of the stud, tar paper, I believe a wood siding, asbestos shingles that are painted. Okay, upon removal (by the landlord/handy guy) the insulation was not that damp...at first. But upon getting to the outside celotex...the insualtion was more damp and the celotex like fiber board was soaked,... bulged from it being filled with water. No real signs of stud rot damage or rot damage at the bottom plate which was surprising. Currently waiting for the wall cavities, 4 or 5 cavities, to dry out...the. landlord ran fan at it.He came back days later after it was dry, still in the winter, and installed fully plastic encapsulated fiberglass insulation (used for sound barrier (why he used this is beyond me). It seemed to fit relatively well, friction fit, inbetween the studs. Enter *me* in the mix. Landlord now wants *me* to do the job. Lady is fussy about sheetrock joint compound/sanding mess and I can do the work often with no sanding. So I met her there the other morning, only for me to pull away the insulation he put in, to find it just dripping inside up against the tar paper...running down the tar paper. No roof leak. New roof. No ice daming. Actually any snow we had, had already melted before he insulated, and yet all that water showed back up in the cavity again! I was able to look up past a 1/2 inch void to the outside of the double to plate with a bright light and saw the roof boards near the eaves and they are not wet nor any black mildew on them. It had only got down to about the mid 20's that night also. Not 20 below, like how we had it a couple times! The apt. is NOT a sauna. I detected no moisture (from showers, cooking etc.) AND, she said she hasn't even used the electric baseboard heat since the problem surfaced! So that rules out the extreme temperature difference between the heater and the outside tar paper that is just inside from the asbestos shingles and original wood siding. Theories on how these wall cavities are reaching the dewpoint? And why isn't the wall all rotted inside as one would maybe suspect?! It's like this problem just happened? Although...just ONE stud showed early signs of deterioration to the outside 1/2 inch, vertically, with it being kind of black and a little punky ( a LITTLE...not much). So,...did the plaster crack let in moisture? Or, did the moisture problem cause the plaster crack? And I don't know if I should bother to put a plastic vapor barrier up over the repair area, even though the rest of the house has none? Maybe this wo dmake it worse in case moisture seeped aroudn the edges, and then trap it in the wall? I think everyone here understands the concept that when hot moisture laden air meets a cold surface, the moisture converts to water on the cold surface. But in a situation like this, it is a little harder to get a mental image as to why this is doing this, to the degree it did. I dug into the cavity next to these and the insulation was bone dry until I hit the soaked celotex! again. Same thing. But that cavity is still over the heater at the outer edge and the landlord should have stripped out that cavity to. I am thinking about buying a moisture meter and probing the apt.'s outside walls in the apt. that are not above a heater, to compare with the cavity I just mentioned about.

Hello, I just bought a house in NC that was bult in 1956. The blown attic insulation is, well, 'old' and seems paltry. There are 2" ceiling joists and the insulation is about level with the joists. I have to repair two sheets of ceiling drywall soon, which made me think about having to deal with the insulation that will come down and then how to replace it. I could just throw it in a bag and return it to the attic but there's a larger issue. In my situation, is the existing insulation so old/worthless that I should remove (vacuum?) it and start over or should I just add to it? Does the proper amount (thickness) to add depend on what type of blown insulation I use? I'm glad someone else confirmed the 'shouldn't compress ceiling insulation with floor boards' theory; I always wondered about that. Sleeper 2*4's over the existing joists wil be my solution to be able to use the attic for some storage.