This is great post because I get involved with a lot of builders and plasterers (
is that spelt right) who PVA everything in sight.
I've had a lot of plaster work done and the first thing they do is PVA bond the area to prime for plaster.
The problem I had was my bathroom walls were wonky so a plasterer came in and skimmed it.
To fix the skim to the existing plaster he applied a thinned down wet coat of unibond and then went on to skim the wall to get a perfect but thin plaster skim.
THEN the tiler came in, primed the skimmed walls with "proper" primer, (I also used BAL tanking kit on the heavy use area) and he then came back and tiled.
IF there is a point to the post I think it might be that PVA and UNIBOND if used properly (ie by the wet trades when applying plaster) then its a useful boding agent for a builder.
Half my house is unibonded prior to plastering.
Oh yes and one thing I was told (a tip) is never let the PVA dry out. Plasterer said he sometimes goes to a job where the owner has "helpfully" unibonded the area for him a week prior so its dried out. He tells me only wet and week is the only way for it to stick to the plaster and substrate.
[The walls were so wonky a skim coat was applied]
Please tell me if I have got any of this wrong.!
Footnote: Please note words used above describe the same material: PVA, Unibond, PVA Bond,