Prep for Drylined walls prior to painting

[Simes123]

Hi - have been doing some bathroom renovations. Will soon, I hope, be ready for painting the wall I had to strip back to studs for some plumbing work.

All the walls in the (old) property have been insulated and drylined (no skim coat) when it was converted. So I'm going to do the same for my renovated wall. I've not done this before, so hey ho, but when it comes to painting, should I do anything to the Gyproc panel before painting? What about the joint filler?

Is this a case of using a mist coat(s?), or should I be using some kind of primer? Primer (if required) on the whole wall, or just the joint filler? I'm hoping I can just mist coat it, but if that is the path to doom, I'm happy to prime (or do whatever else is necessary).

Thanks,

Simon

 

[oldgreymouse]

Simon, have you used the green waterproof gyproc board? If so, generally you can tile straight over this or if you are looking at paint, then I would most likely go for an oil based primer, then an undercoat and a topcoat of an eggshell finish or perhaps the Dulux diamond finish.
You will need to have a look at gyproc easi-fill for joints and maybe even just gyproc primer to seal.

Another way, could be to go to zinsser bulls eye 123 for the first coat then a couple of coats of good quality silk finish or even just go for the diy store bathroom paint if you want a colour off the shelf.

You need to ask, how damp will the bathroom get, is it a shower only, do you have window vents as well as extractor. All are important factors.

 

[Simes123]

Hi,

Sorry - I should have provided more info.

The Shower area itself will be boarded with Aquapanel and tiled. The area I'm unsure about preparation is outside of the "wet zone" and is boarded with standard tapered edge gyproc plasterboard, joint filled with easy fill. The finish for this area will be an acrylic eggshell paint - Craig and Rose I expect or some kind of bathroom paint. This has to go onto fresh plasterboard/easifill, so I'm not sure what I should do as a base coat.

I'm also a little unsure on what I should put "behind" my Aquapanel. One wall is stone, airgap, celotex, osb, aquapanel, and the other is a stud wall, with glass fibre insulation, osb, aquapanel. I've now learnt that aquapanel is not waterproof, but water tolerant. So I need to protect the OSB somehow.

Simon

 

[Simes123]

P.S. - The room has an extractor, and is reasonably large, doesn't get particularly damp.

 

[oldgreymouse]

Aquapanel, should be waterproof, I have been using this for several years now to form the insides of shower cubicles. You need to use the correct screws and the right sealant for edges and corners. Aquapanel seems to have the name all over the place but on different products. Some cut easily with a jigsaw, others ruin a blade in half a minute and I cut it with a diamond blade on a 125mm angle grinder

I tile straight onto aquapanel as directed and if you have waterproof osb behind then that's fine.

As for the area outside the wet area, shame they could not have used the waterproof gyproc.
Painting, then start with zinsser 123 for the first coat, check what undercoat Craig & Rose suggest under their eggshell, if it's oil then use that, but I think it will probably be waterbased undercoat so use that.

 

[Simes123]

Thanks - it's not too late for the plasterboard - I haven't put that up yet, so could always get waterproof plasterboard. I didn't think it necessary, as I'm using aquapanel completely within the shower; it's also 1.5m on the long dimension, and thus the ordinary plasterboard is a long way from any splashing, on the other side of a glass end panel, also in water's way. Further, I planned to use ordinary plasterboard because I could get it in a 3m length easily Before my renovation, they'd used ordinary plasterboard, even in the shower area. It wasn't that bad overall, but at the very bottom of the shower area it had clearly been affected by water.

I hadn't realised C&R Acrylic Eggshell also needed an undercoat on plasterboard? Good job I checked. So are you saying Zinsser 123, some kind of undercoat, and then the acrylic eggshell? I'm only hesitant because of cost - this project started with me saying, "I'll just adjust the old shower door hinge". Some £1500 later, I'm still finding things I need to buy

 

[oldgreymouse]

Yes, do use an undercoat on top of the zinsser 123, it will give you a better surface for the C & R eggshell. Either use the C & R undercoat or Dulux waterbased as I think the eggshell is acrylic.

The old way of doing shower walls was with ordinary plasterboard, but in time the tile grout fails, letting the water into the back which as you are aware, the ordinary plasterboard has no waterproof properties so it fails.
With the advent of aquapanel and other boards this is no longer a problem unless poorly fitted.