Lime plaster with a gypsm skim coat. Advice needed please :)

#1
Hello

I have an old house in the UK which I am renovating. The walls are stone and on the inside have been lime plastered then had a gypsm skim coat on top. When peeling back the wall paper some of the Gypsm has come off which I am almost certain is due to the moisture from not letting the walls breathe.

My question is can I just remove the Gypsm and then skim a light coat of lime plaster over to get a finish? and if so how will I prepare the lime walls under the gypsm (do I need to wet them down, pva etc?) Also what is the best mix and type of lime needed to apply this top coat.

Thank you in advance.
 

Squarehead

Well-Known Member
#2
The lime plaster backing coat.... how old is it?
 
#4
Not sure I would say 40 years judging by the type of wall paper that was over it maybe 1950's

Looks in really good condition. Good enough to paint if it wasn't for some swirly scratches here and there which Im guessing were a key for the gypsm.
 

Squarehead

Well-Known Member
#6
Steamer caused plaster to lose key (gypsum has no chemical bond with sand backing coats, so can be weak) knock off rest of loose plaster. SBR the whole lot, then thick coat of pva on top of that and skim with multi finish rendering mesh embedded.
 

carys

Well-Known Member
#7
Hello

I have an old house in the UK which I am renovating. The walls are stone and on the inside have been lime plastered then had a gypsm skim coat on top. When peeling back the wall paper some of the Gypsm has come off which I am almost certain is due to the moisture from not letting the walls breathe.

My question is can I just remove the Gypsm and then skim a light coat of lime plaster over to get a finish? and if so how will I prepare the lime walls under the gypsm (do I need to wet them down, pva etc?) Also what is the best mix and type of lime needed to apply this top coat.

Thank you in advance.
if your not going to start again and that the only way whith lime Id scawer the wall dampen the wall down and skim over whith lime finish plaster that 50 50 chance it hold. Personally if it all loose I'd start from scratch and it be a life time job then. The only other option you got is overskim