Bathroom plaster/plasterboards prep before tiling & pain

5 Apr 2012
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In and around London
United Kingdom
I'm after a little bit of advice concerning plastering in the bathroom we're moving upstairs (early 1900s house).

Three of the four walls are interior studs with moisture-resistant plasterboards fixed. One wall is exterior brickwork with original plaster. The ceiling is plaster and lathe, which was covered with textured finish at some point, but now has been boarded over with moisture-resistant plasterboards.

I'm going to be tiling the exposed (i.e. not behind/under the bath) walls and floor, and taping/jointing then painting the ceiling white (no plaster skim).

Basically wanted to know what prep/coating/treating should be done before tiling and painting:

1) MR plasterboard stud walls. Should they still be taped and jointed before tiling? Do the boards, or filler joins, need to be coated/prepped with anything? What about the un-tiled boards behind the bath?

2) Plastered brick wall. Should this plaster be coated/prepped in any way before tiling?

3) MR plasterboard ceiling. Once taped and jointed, should it be coated/prepped before painting? Any particular emulsion paints ideal for bathrooms?

I'd gathered some information from this webpage here:

...but just needed some clarification. I've seen the term "tanking" a lot. Does this just mean adding non-porous/waterproof coating protection?
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1 MR stud walls dont need to be filled before tiling as the tile adhesive will fill out all the joints in the plasterboard, do not paint or treat boards before tiling as it could affect the adhesion of the tile adhesive. I would give the boards behind the bath a quick skim of filler just to seal the joins. When you seal the rim of the bath to the tiled wall with silicone fill the bath with water first and leave till the silicone has set.

2 Im not sure about the plaster wall iv only ever tiled onto plasterboard.

3 Ordinary matt emulsion should be fine for the ceiling but you can get paints specifically for bathrooms, if you use a paint that has a sheen i.e satin or silk finish make sure you put a coat of matt emulsion down first or you will see every join in the plasterboard.

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