Where to seal with PVA?

[womp]

A) ordinary plasterboard before multi finish
B) wooden lath before bonding coat
C) previously finished plaster, cleaned up, before multi finish

Additionally, what are your thoughts on PVA as a bonding coat, generally and in the above situations? I've heard it isn't much good for bonding and a good spray soak of water will combat suction just as effectively.

Excuse the brevity, sent from my phone.

[Colour Republic]

A) ordinary plasterboard before multi finish
B) wooden lath before bonding coat
C) previously finished plaster, cleaned up, before multi finish

Additionally, what are your thoughts on PVA as a bonding coat, generally and in the above situations? I've heard it isn't much good for bonding and a good spray soak of water will combat suction just as effectively.

Excuse the brevity, sent from my phone.

A) No, not unless the boards are old and have been up for some time (I assume you mean bare plasterboard?)
B) Define in what context? You wouldn't normally plaster wooden laths anymore unless you were undertaking a resoration project which in most cases would mean lime plaster.
C) Yes but how strong that mix is and at what ratio would depend on a case by case basis

[womp]

B) just bits of lath that were exposed hacking back plaster to facilitate fixing of new stud wall. Mostly brick but enough lath for the bonding coat to penetrate behind...

When I refer to PVA for bonding coat I mean the one applied just before finish plaster, and plastered over just a it becomes tacky. ( with concrete render over tacky PVA it still fell off and the tacky coat went back in the bucket with it. My limited experience of such ad mixture/primer)

[womp]

B) that lath should stay put, too big a hassle for it not too, might effect the ceiling...I'll try and take the wall paper off it first to make sure. You say like plaster?? Is that the same as lime render or do I just need to add lime to my bonding plaster mix?

slightly off topic: Bonding coat is more similar to filler than multi finish is.. Workable, bonds most stuff, almost any thickness.guess it must be slightly thicker coat and is less adhesive, worth a look/try at a quarter the price of filler.

Bought it to fill the inch or so wide gap where the ceiling was removed to build new stud wall in.

[cotswold builders]

If its not lime plaster on the laths, use carlite bonding as backing plaster.

You don't use pva on render.

[womp]

How can I tell if it's lime plaster or Carlite?

Lol, no don't pva concrete render, but under a lintel you might want to try.

[royaloakcarpentry]

Under a lintel you don't PVA either....use EML.............soldiers, board and skim.

[womp]

Or if you have no idea what EML is you might find a web site that suggests PVAing or even glueing plasterboard on.

So, do you PVA taped joints?

[cotswold builders]

It sounds like you have a few gallons of pva you want to use up.

[rps-plasterer]

EML= expanded metal larthe ,
if you try to render a head with concrete ,in fact if you try to render anything with concrete it will fall off.
concrete and render are different things.
will occasionally use PVA as a bonding agent under render but only inside , you should really use SBR .
as for under your concrete lintel , would probably just apply bonding directly to it. unless of course theres a thumping great hole where the cavity is ,tht nobody bothered to fill in properly, in which case would stick PB to it using dry wall adhesive.
as for using PVA on the boards that you've taped ,you shouldn't have taped them, self adhesive skrim is all you needed. however, now you've done it ,would probably splash with a week solution of PVA or use bondit/ bluegrit.