Please help, paint peeling off plaster

[bear73]

Yes the plaster was dry and yes I did do a 50/50 mist coat with Dulux white matt paint first.

The area was skimmed a week ago, it's a doorway that's been plasterboarded up and then skimmed. The main area of the door (the plasterboarded bit) seems ok but the edges where the skim goes over onto the existing painted wall is flaking. I used coarse sandpaper the sand the peeling areas back until smooth and mist coated again and exactly the same has happened. Within a hour it was cracking and peeling.

The wall is a very cold wall (backs on to garage). It's uninsulated as our walls are old solid walls BUT the plasterboarded bit is insulated as has celotex on the reverse of the old doorway and that bits fine.

We had problems during a recent refurbishment of the house with paint peeling. We had professional decorators and it was happening on all the freshly plastered walls that were external and north facing. I'm presuming it's something to do with the cold wall but not sure.

Seeing that mist coating is not working I would really appreciate advice about what to do next. It's now all uneven as the central area is fine and the edges are patchy, peeling and awful.

Really annoyed as I prepared well, did my homework and it looks pants!

Thanks

 

[misterhelpful]

My suspicion is that PVA has been used to achieve a good bond where the new plaster joins the existing. This will cause cracking/crazing/blistering/peeling of the new paint as it will not adhere properly.

You could try either a slightly thinned (with white spirit) oil based undercoat or something like Zinsser Gardz on the problem areas before repainting with the emulsion. Prep the problem areas first and hopefully this will do the trick.

 

[bear73]

Thanks, I've ordered some of the Zinsser Gardz you recommend and hopefully that will do the trick. Should I now sand back as much as I can and then coat the areas affected with the Zinsser Gardz? I really hope I can get it looking even. Thanks for your help.

 

[misterhelpful]

Get the areas looking as good and smooth as possible before applying the Gardz. You can use good quality fine surface filler if you need to.

 

[Jameswren]

I agree - put some filler on then rub down to get the area flat again.

 

[Robbie uk]

I doubt the temperature of the wall would make the emulsion come off. I think Misterhelpful is on the right track regarding the PVA.