Normally fresh plaster is about 30 days before you paint it I think. Someone messed up somewhere along the way.. Sounds like a nightmare job..

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thanks, I think the plaster is old but not sure. House is pretty old. I assume they didn't re plaster the whole thing instead of just drywalling it.

 

Do not assume that they did not put new plaster up. I did a house a while back that was flipped (I may never work for a flipper again...bad experience). They whole house was gutted, and new plaster. Sounds like in your case the paint might have been applied before the plaster properly cured. Sounds like a nightmare to fix.

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wipe it down with vinegar. That will harden it a bit. (newbies!) (and any paint rep worth a 5hit would have told you this already, just sayin.)

 

Wouldn't he have to remove all of the existing coats of paint to do this?

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Sounds like saponification, and after saponification comes crumbling. Loxon is as good as anything on plaster. As PAC said , wash down with vinegar first to lower the pH.

 

The other thing to consider is any paint that hasn't been peeled off yet will probably pop off once another coat is applied. The new coat will shrink as it cures and will more than likely pull any remaining right off the plaster. A large portion of it anyway. It really needs to come off to fix this properly.

 

This whole thread reminded me that I had a conversation with a guy at my paint store. One of the local paint companies is having a GC insist that they paint plaster that is not dry. There is no heat in the building. The GC says he has to finish the job. The owner of the paint company is having the GC sign off on so he will take all responsibility. Even if the GC signed off I would have trouble doing the work. They are screwing the home owners. I would have to inform the home owners what the consequences will be for having the job done on time.

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I hate when the GC's pull this sort of thing. We had a local McDonald's franchisee who built 5 or 6 McD's restaurants and when it came time to paint the interiors, the GC would push the painters to the point that they were painting over WET joint compound. Yes, wet JC. I actually witnessed this in action and the mud literally would wrap around the roller!!!! Of course, you know who gets the blame.....

 

In addition to failure as a result of saponification, I’ve seen a lot of finish failure with traditional lime plaster originally finished with soft or even oil bound distemper, then painted over without removing the distemper. Latex over hide glue and chalk when coating over soft distemper typically results in progressive failure.

 

Traditional distemper has a high organic content (contains animal based components) providing the fat(oil) needed for saponification. So the distemper reacting with the lime in the plaster is causing saponification, which in turn leads to paint/plaster failure.

 

Article describing why oil bound distemper fails and most likely relates to the OP’s situation:

http://patrickbaty.co.uk/2009/05/10/the-problem-with-distemper/

 

Good article, and goes a long way in providing one explanation why plaster walls with multiple coats of paint that never caused any problems can suddenly become troublesome when doing a repaint.

 

Calcimine.

 

Calcimine and distemper are basically the same thing