Bathroom - boarding, skimming, painting AND tiling advice.

[Russtavo]

Hi, I'm due to start my bathroom rennovation soon. I plan on using Moisture Boards for the walls, plaster skim, paint the majority and tile splashback areas.

I have three Questions:

1. Do I prime the plasterboard before skimming? If so, do I use BAL WPL coating, PVA or something else?

2. Do I seal the plaster skim before painting? I'm worried about PVA because of the tiled areas, so what should I use?

3. What kind of paint is most suitable for the moist conditions?

Much appreciate any advice

 

[Richard C]

1. Do I prime the plasterboard before skimming? If so, do I use BAL WPL coating, PVA or something else?

No primer needed before skimming standard wallboard but if it’s MR board, it must be primed;
http://www.british-gypsum.com/produ...le_plaster_bonding_agents/thistlebond-it.aspx
If your tiling the PB, don’t skim it; it's not necessary & affects the weight of tiles you can hang, tile straight onto it but if it’s a wet area tank it with BAL WP1; better still use a waterproof tile backer board. Never use standard PVA for priming anything other than before plastering; if you use it before painting, the paint wont stick & if you use it on a tile base you tiles could fall off.

2. Do I seal the plaster skim before painting? I'm worried about PVA because of the tiled areas, so what should I use?

To seal new plaster, you need to apply 2-3 wash coats of ordinary matt emulsion thinned 25-30% applied in quick succession, let it dry for 24 hours & then apply your chosen finish coats. New plaster must be allowed to dry out thoroughly for around 10 days before painting or tiling. I may have you wrong but don’t plaster, paint & then tile, bad idea & not necessary.

3. What kind of paint is most suitable for the moist conditions?

Moisture resistant bathroom paint but, TBH, I only ever use standard emulsion.

 

[Russtavo]

Thanks for the excellent advice Richard - but presumably I will have to tile on the plaster skim if I'm having both paint and splashback tiles on the same wall?

If I read your post right, would you recommend:

MB --> BAL WP1 (wet areas) and Thistlebond (other areas) --> Plaster skim --> Adhesive+Tiles then paint the plaster up to the tiles. ?

Is it ok to skim on top BAL WP1 and could you also use it on top of the skim before painting? Sorry to be a pain!

 

[Richard C]

presumably I will have to tile on the plaster skim if I'm having both paint and splashback tiles on the same wall?

If ½ tiling, decide where your tiling up to, put a line on the wall & ask your spread to skim down to it; he will then (hopefully) “waste” the plaster into an area around 50mm below it. Then just tile away & when you’re finished, you have nice tiles to the floor & a nice plastered wall above the tiles.

If I read your post right, would you recommend:
MB --> BAL WP1 (wet areas) and Thistlebond (other areas) --> Plaster skim --> Adhesive+Tiles then paint the plaster up to the tiles. ?

WP1/tape on PB in wet areas & tile over that; only skim where your not tiling as above; MR board must be primed for plaster skim or the plaster won't stick. Only use decent flexible trade adhesive & grout not cheapo DIY shed crap. Large tiles (over 300 x 300mm) must use cement based adhesive not tub ready mix.

Is it ok to skim on top BAL WP1 and could you also use it on top of the skim before painting? Sorry to be a pain!

No, no, don’t under any circumstances do that; can I ask is this a conventional bath/shower room or wet room?

 

[Russtavo]

It's a conventional bath/shower room. To be honest I'm planning just a small tiled area above the sink, and all over the sides of the bath. I'll have to make a wooden frame for the bath, but not sure what to cover it with - is aquapanel the best stuff? For the shower cubicle itself I'll be using the wetwall stuff.

Ok so I'll have to mark out exactly where the bathroom units are going and the tiled areas and do this:

Walls (Tiled): MB --> BAL WP1 --> Adhesive+Tiles .
Walls (Painted): MB --> Thistlebond --> Skim --> Paint.
Bath: Aquapanel --> BAL WP1 --> Adhesive+Tiles.

How's that sound?

 

[Richard C]

You only need to tank the PB with BAL WP1 in wet areas, outside wet areas you can just tile straight onto it.

If you’re using Aquapanel for the bath panel, you can just tile straight onto it, no need to tank it with WP1.

Walls (Tiled): MB --> Adhesive+Tiles .
Walls (Painted): MB --> Thistlebond --> Skim --> Paint.
Bath: Aquapanel --> Adhesive+Tiles.

 

[Russtavo]

Brilliant thanks so much Richard

Can I pick your brain further and ask another question:

I'm going to plasterboard my kitchen extension soon and am worried about adequate support for the cupboards whilst avoiding cracks in plaster.

The blockwork is Thermalite - which is soft and crumbly. Space is tight for the kitchen plan, so my idea is to dot & dab 9mm board to it but use extra dywall adhesive around the areas supporting cupboards, then use long frame fixings going right through into the Thermalite. Does this sound ok? Many thanks!

 

[Richard C]

Don’t use 9.5mm boards, bad idea; always use 12.5mm. If you dot & dab the boards close to the wall, this will provide good support & the frame fixings through into the blocks should be fine; a little extra drywall where the fixings are would be a good idea. Use extra drywall around the board edges to give more or less continuous support here.

Or do a proper float & set plaster job on but it is more expensive.

 

[Russtavo]

Will do!

 

[Russtavo]

Hi Richard, can I hijack my own thread to ask another question?

I'm going to fit a new low-profile shower tray soon and the instructions say to use silicone based adhesive for fixing. Can you recommend the best product for this? Many thanks

 

[Richard C]

It’s important with any tray that it’s firmly supported & I find a WBP ply base is usually best for this. I fit mainly stone resin trays with are bedded on a weak mortar mix; no experience with the Bathstore tray but the website says it’s acrylic capped with a resin foam core construction but am unsure if that means it’s a GRP based construction or is stone resin. Stone resin will be very heavy & it’s basically cement mixed with fibres.

If Bathstore say to use slicone, I’d go with that as your gurantee in the event of problems will depend on it. Unlike a silicone bead, no need to use anything special IMO so a tube or two of cheap bathroon silicone will do, the important thing is to ensure the tray is fully supported without any stress points; particularly important with stone resin as will not flex & is very brittle.

 

[Russtavo]

Thanks Richard, I have overboarded with WBP ply already. The tray is not heavy so I guess unlikely to be stone resin. I just figured some brands of Silicone were better than others, no worries. I'll watch out for stress points