Hello,
I own a 1920s single story with finished basement and finished attic (accessible knee walls on both sides). The main floor has nearly all plaster walls and ceilings. My question is about the main floor bathroom.
The prior owners did some short term cover up fixes that are failing. Basically, where the plaster integrity was compromised, they just mudded and painted cracks to conceal. While I was addressing it, it appears that the damage was caused by an undersized bath fan (upgraded), roof leak (repaired), and general age/settling. All of that also caused a couple of lath nails to work loose.
I'm at the point where I've exposed the cracks and removed the plaster in areas where it failed significantly. The main area is the top two lath along the top edge of the exterior facing wall, which has given me a good view into the wall itself. The insulation is giving me pause.
The attic has wood shaving insulation with fiberglass batts overlaid. I suspected the main floor walls themselves had the wood shavings, because they get rather cold, especially when trying to use the bath on the exterior wall. This project has confirmed it.
So I'm wondering what, if anything, I should/can do to improve the insulation. To further compound it, I will have a new roof put on in the next couple years (likely new decking) and have the attic insulation cleaned out and updated at that time. So not sure if exterior walls could just be done at the same point.