"What did I do wrong?" Topic

I was working on my bathroom ceiling over the past couple of days. First I scraped all the loose paint. Then I patched with medium weight joint compound. I waited a day until it was dry. I sanded. I skimmed it with joint compound…thinned. I let it dry for a day. I sanded. I had my wife look for imperfections and I filled those. I let it dry over night. I spot sanded a few spots.

Tonight, I started priming. Things went well until I noticed a bubble in the shower area. I rolled over it and the plaster had come off. It came off in several places and I scraped some substantial areas away. I've never had this happen before and I've had some experience with drywall and joint compound. The only thing I can think of was the humidity did not allow the "mud" to dry all the way.

So…what did I do wrong?

First I scraped all the loose paint.

Did you scrape it all off? Since it's a bathroom, I assume it was gloss or semigloss paint, and I suspect that might be your problem. I've noticed that even good primer will sometimes bubble when applied over semi-gloss and gloss paint.

If that was the case, there are a variety of deglossing agents (liquid sandpaper) that work well.

No. The old paint even peeled away…which means the previous painter may not have prepped the ceiling well.

The perplexing thing is that the areas that had mud were the ones that really had this problem.

I tend to agree with enfant perdus. You might want to use a deglosser to remove any of the chemical from the gloss that seeped in.

I can give it a try. BTW, I think the ceiling is eggshell. Thanks for the help all.

John

A couple of days late to this post but let me throw out a few other possibilities. I am a landlord several times over so I've run into similar problems with some of my older properties. A few ideas:
#1 – The above deglosser scenario may be it. I have used a heavy dose of Spic n' Span cleaner (powder) in a bucket of hot water to scrub down the walls before painting.
#2 – I've seen enamel paints over latex paints and vice versa. They don't always cover over each other.
#3 – Being a bath (or kitchen) you tend to get a lot of humidity and outright moisture. Moisture sitting on any surface will attract dirt, oil, soaps, etc. This stuff can seep into old dry plaster and loosen/weaken it.
#4 – Make sure you do not have plumbing running above your weakened plaster area. Is it possible you have a leak or spill issue above the tub/shower in question?

Just some stuff to consider…