Can you paint straight onto MR Plasterboard (or is a sealer/primer needed)?

[DIYNotIan]

Hi all

I'm going to be putting up some MR plasterboard on the bathroom ceiling today. There'll only be one or two joins, so I won't be having it skimmed (that being said, I've read in places that you shouldn't skim MR plasterboard anyway).

What I don't know is what prep the MR PB needs once up? I've done some reading on the subject and there's a whole load of different opinions and answers. So I wondered if anyone here can set me straight please? Does it need a sealer? A primer? Or just paint straight on?

In case it makes a difference, the room is part ceiling part skeiling, so I will be looking to use plaster or whatever to round off where the two boards meet.

Many thanks

 

[Wayners]

You can plaster when building is air tight and dried out.
I'd tape and fill joints and screw holes
Apply gardz
Emulsion using something like perma white.

Also pack behind with plenty of insulation. Possibly fill the void. I filled my void and ceiling is perfect after 10 years. That will stop board getting cold and condensation forming on the surface.

 

[DIYNotIan]

Apply gardz

Is that needed if the PB is already moisture resistant?

Also pack behind with plenty of insulation.

Yep, that's all done thank you. So it's onto the plasterboarding now...

Thanks for the reply

 

[Wayners]

Gardz will prime the filler more than the board.
Could use a acrylic primer undercoat or depending on paint used, look at application data sheet for advise.

 

[DIYNotIan]

OK, cheers, I'll look into that. I have got some Zinsser Bullseye 123 that I usually use for priming. I'll check the tin to see if that is suitable...

 

[Wayners]

OK, cheers, I'll look into that. I have got some Zinsser Bullseye 123 that I usually use for priming. I'll check the tin to see if that is suitable...

That will work fine

 

[John D v2.0]

I had the same question before and after research I found knauf's version only needs priming if you're going to skim it (presumably due to the weight) and is fine for (presumably jointing) and then painting directly. I didn't have any joints because it was an ensuite ceiling.
See there info at their web site https://www.knauf.co.uk/systems-and-products/high-performance-boards/moisture-panel