Peeling wall

[dabomb3k]

Hi guys, i had a problem with a peeling wall which was an external wall in a back room of my house, the paint would just peel off the wall in quite large chunks, this problem was there when i first purchases the property

when i had some work done, a mate who was just learning plastering said he would plaster the walls for free for me...

the idea to me was great, i got new plastered walls and i didnt have to pay, especially with the other work i needed to do in the house..

he pva's the walls and provided a 2-coat skim of plaster over them for me..

unfortunately he also offered to paint the walls for me and didnt do a mist coat or diluted layer and just rollered straight onto the walls (giving 3 coats)

now on the external wall, i am getting peeling and bubbles, i presume i can just take it back to the bare plaster and re-paint the right way (correct??) but will i have a problem as it was skimmed straight over the previously bad wall aswell?? the wall was never knocked back, just pva'd

and also, on the internal walls now, if i wash them with a damp cloth (if say, someone marks them) the paint washes off with the cloth back to the plaster..

im looking for the cheapest but practical solution really, with the internal walls, can i just apply an undercoat layer now and then re-paint or will i need to go back to bare plaster

and with the external wall, do i need to scrape the whole wall back and then re-paint with a mist coat, and if so whats the best way to get the paint off the wall?

sorry for long post and thanks in advance for any help!!

i should add that the external wall is a very old lime plastered wall (but i understand lime plaster was pretty good for retaining damp?)

 

[joe-90]

Have you put a damp meter on the wall? Sounds damp to me.

 

[dabomb3k]

thanks for quick response, well i had conflicting information about that.

one guy came out and put a meter on the wall and said its damp.

then another guy said because its lime plaster its known to soak up water anyway so will often fool the damp meter into reading damp when its actually just cold spots.

my kitchen is the next room across and the bathroom is directly above so i did wonder about that..

i thought maybe it could be coming from outside, but there's quite a thick pebble dash render to the outside, and i dont get any problems in the room above or to the side of that room.

the guttering has been renewed in one part, but is pretty old above that room and wall.. however as i dont get any problems in the 1st floor room, i presumed it wouldn't be the guttering causing it

also the "problem" happens reasonable high up the wall so isnt likely to be rising damp (well over a meter high in parts)

 

[oldgreymouse]

This job sounds odd.

First off, have you had a gypsum plaster coat put on over over a lime plaster? If so the lime plaster has now been sealed in and it's properties lost.
Lime plaster needs to 'breathe' to do its job, it must not be sealed, either with pva glue or 'vinyl' paints, only non vinyl paints or lime wash should be used.

However, what paint did you use as the first coat on the new plaster, was it a non vinyl paint such as Supermatt? If this was applied without thinning, then it has dried too thick without sucking into the plaster, which is why it may rub off.
Another reason may be that the plaster finish was 'over polished' and a hard glaze had come onto the new plaster surface that also prevents the paint taking up into the plaster.

Last of all, what did you intend to do with an 'undercoat layer'