Oh no, need advice about removing paint from newly plastered walls

[NightNightBadger19962]

Long story short, we have recently painted over new plaster, using dulux supermatt but not diluted properly (had researched, but believed the wrong advice, realised mistake part way through). Now we have applied the colour, we can see it has not bonded to the plaster at all. It will all have to come off, it's a large area - how do we do it? Steam? And then what next?

What do you mean by "not bonded to the plaster"? Do you mean it's flaking?

Do not steam as it will leave a sticky, lumpy mess. Sand it off then seal the plaster with diluted paint - I've used bog standard Trade Paint, which is thin anyway but you can dilute 10/90 or 20/80 if too thick. The smaller quantity is water, the larger paint.
Two coats of that will dry quickly then you can paint over.

No experience of Dulux Supermatt but I use One Coat, again diluted 80/20 as full strength dries to fast and cracks.

Did you let the plaster dry out fully?

We did let it dry out. Just didn't seal/mist coat effectively we think. Thanks for the advice about sanding. It's actually coming off in strips with a metal paintstripper tool ok. We are wondering if it is just an issue because the paint we have put on top is a kitchen/bathroom one and therefore a bit plasticky and heavy after two coats? Going to test the other bit with a different paint to see if we can afford to not strip that one completely (the ceiling coat has gone on fine, just a matt emulsion - but may have problems later on?)

If you're painting on to newly plastered walls you should firstly sand the walls (this is very important as it acts as a key for the paint to stick to), then do a first coat of diluted paint, not too dilute about 80/20 is right.

TBH I'm guessing, the effect you're having is most likely because you didn't sand the wall first, rather than not diluting the top coat.

Mine fell off in one big sheet! Maybe yours has bonded more than you think!

Oh chatty [shocked]. OK, we have determined that the only wall affected is one wall in the bathroom - an internal wall, the other one is external? We have taken it back to the plaster on that wall, but the ceiling and other wall it simply won't come off, and none of the same problems, so we are going to sand the edges (and the plaster Lottie) and then have another go. Lottie, the plaster on this particular wall IS super smooth. I will definitely sand in future. Thanks all feeling slightly more cheerful 🙂