Hello all,
After a spot of advice on the use of diluted PVA or not when using Bonding...
I've patched up some interior walls with bonding coat in weak areas (area-wise about 10% of the wall). The remainder of the wall is emulsioned paint over plaster (prob about 20 yrs old).
I PVA-ed the painted part before skimming with quite a strong mix of PVA water (about 3:1). The adhesion and setting of the skim was fine.
Where I've struggled is with the bonded areas. I was taught that when using bonding, if you PVA over it (the case in hand was within 24 hours) that it would restrict the moisture coming out of the bonding and could cause the skim to bubble.
However, where I have bonding I have not been so efficient getting back to it, so it had dried out fully to a light pink.
I applied water only and then before skimming I applied a second pass of water to try to reduce suction out the skim. Hoped this would do the trick - it didn't quite!
The first coat over the bonding areas dried out fast and crazed a bit. It didn't lose adhesion, and fortunately on the second coat covered just about - but didn't allow much scope for trowelling, as had gone off quite significantly compared to the adjacent skim over the painted areas.
Apologies for the essay, and assuming you've not fallen asleep - should you just use PVA/water mix as normal and treat it all the same once dried out fully?
From the posts I found on this subject, consensus seemed skim promptly after bonding, as moist bonding is easier. And PVA isn't quite the no-no I thought.
Advice appreciated as always.
After a spot of advice on the use of diluted PVA or not when using Bonding...
I've patched up some interior walls with bonding coat in weak areas (area-wise about 10% of the wall). The remainder of the wall is emulsioned paint over plaster (prob about 20 yrs old).
I PVA-ed the painted part before skimming with quite a strong mix of PVA water (about 3:1). The adhesion and setting of the skim was fine.
Where I've struggled is with the bonded areas. I was taught that when using bonding, if you PVA over it (the case in hand was within 24 hours) that it would restrict the moisture coming out of the bonding and could cause the skim to bubble.
However, where I have bonding I have not been so efficient getting back to it, so it had dried out fully to a light pink.
I applied water only and then before skimming I applied a second pass of water to try to reduce suction out the skim. Hoped this would do the trick - it didn't quite!
The first coat over the bonding areas dried out fast and crazed a bit. It didn't lose adhesion, and fortunately on the second coat covered just about - but didn't allow much scope for trowelling, as had gone off quite significantly compared to the adjacent skim over the painted areas.
Apologies for the essay, and assuming you've not fallen asleep - should you just use PVA/water mix as normal and treat it all the same once dried out fully?
From the posts I found on this subject, consensus seemed skim promptly after bonding, as moist bonding is easier. And PVA isn't quite the no-no I thought.
Advice appreciated as always.