Drywall compound separates from drywall
Previous homeowners vented clothes dryer into enclosed garage for approximately 2o years. All joint tape has fallen off the ceiling drywall. The wall joints are in a poor condition, but do not exhibit the problem to the extent that the ceiling drywall does.
Replacement tape and drywall compound adheres to old ceiling drywall for approximately one week, then begins to separate at the feather edge, ultimately dropping off the ceiling in another two weeks.
The drywall condition when the home was purchased had a dull brownish color. When I was away from home for 4 months, the drywall apparently dried out to some extent, changing color to more near the original white. The problem was less severe, but still a major problem.
I suspect that "clothing softener chemicals" were added to the wash and vaporized onto the garage ceiling by the dryer every week for those twenty years.
The question is how do I retape the existing drywall for a permanent solution short of tearing out the drywall and reinstalling new drywall? (Yes, the dryer is now vented to the outside wall.)
Re: Drywall compound separates from drywall
if the insulation above this ceiling, or any part of the area above like the joists or the drywall itself, is saturated with moisture or has a high moisture content this would explain your joint compound and tape falling off after it seems surface dry. I'd be exploring the cavity space above for signs of high moisture content, verify no roof leaks, then work from there. you may have to remove wet insulation, remove the ceiling and provide for a means to dry out the area first. the drywall ceiling if previously saturated may not be salvagable and covering it up with a thin layer wouldn't make it any drier or stronger. A moisture probe would be your best indicator. if you can borrow one great, otherwise possibly a worthwhile investment for you to consider.