stud wall & ceiling construction in shower room

[JimLoskot]

I'm splitting a large room up with a stud wall to create a bathroom and an en-suite. I'm also going to put a new ceiling up.
The stud wall will be made from 3x2 and i'm thinking of putting 2 layers of 12.5mm plasterboard on and skimming allround and then using a shower tanking kit on the 3 walls that make up the shower before tiling over.

Does this sound like a good idea or should I use a moisture resistant plasterboard or even the aquaboard in the shower area?
Can anyone recommend a tanking kit and are they easy to use/put on?

I'll be creating new ceiling joists with 4x2 and screwing plasterboard on this before skimming and then painting with kitchen & bathroom paint.

Again does this sound like a good idea, do I need to use a moisture resistant plasterboard or vapour board (the foil backed stuff) or will normal plasterboard do?

Thanks for any help or advise
Jim

 

[Maxsys]

If you are tiling or tanking DO NOT skim, no need, and it will affect the type/size and weight of tiles you can use. If it were me aquapanel for the shower area, no need to tank, but you can if you want overkill, moisture resistant plasterboard everywhere else, and any areas not being tiled do not skim. Any areas that do need skimming just feather it in up to where the tiles will go.

Only use quality trade tiling adhesive and grout, such as BAL, Mapei or the likes.

Suggest you read the tiling sticky, and search through the forum, this has been covered many times before.

Any more questions you cannot fined the answers to, come back and ask.

Oh and don't forget ventilation, extractor fan and windows, without them you will have mould issues.

 

[JimLoskot]

Thanks for your response.
Yes, I'm aware it been covered many times before, have read loads of posts.

If I use the aqua board, do I need to tank the 2 solid walls that make up the shower that have plaster on them or can I just tile straight over these?

What do I use to seal where the aquaboards join up next to each other?

as I'm using 2x12.5mm plasterboard on the stud wall, should I double up the aquaboard as well or can I put it over plasterboard (mainly due to cost as aquaboard is 4x the price of plasterboard)?

In practise is aquaboard the same thickness as plasterboard (I know in the specs it shows it as 12.5mm)?

So no vapourboard needed on the ceiling then?

and any areas not being tiled do not skim.

I presume the not was a mistake?

Thanks again
Jim

 

[Maxsys]

Thanks for your response.

If I use the aqua board, do I need to tank the 2 solid walls that make up the shower that have plaster on them or can I just tile straight over these?

That will depend on the size type and weight of tiles you are proposing to use, plaster skim will only support 20Kg/Sq Mtr and you need to allow 4Kg for adhesive and grout, so 16Kg/Sq Mtr for tiles

What do I use to seal where the aquaboards join up next to each other?

Aquapanel do a special joint sealer, or you can use silicone.

as I'm using 2x12.5mm plasterboard on the stud wall, should I double up the aquaboard as well or can I put it over plasterboard (mainly due to cost as aquaboard is 4x the price of plasterboard)?

you can put it over the top if you want, but why are you doubling up?

In practise is aquaboard the same thickness as plasterboard (I know in the specs it shows it as 12.5mm)?

Yes

So no vapourboard needed on the ceiling then?

No just use moisture resistant PB, and proper paint

and any areas not being tiled do not skim.

I presume the not was a mistake?

yes it should have read any areas BEING tiled do not skim

 

[JimLoskot]

I'm doubling up the plasterboard to make the wall more solid as it runs the length of the room (3.5m), only 900mm of it will be in the shower.

As the aquaboard is 1200mmx900mm would I be better off laying them down on the 1200mm side and going over into the non-shower bit?

Can you skim onto the bit of aquaboard that projects beyond the shower area?

She hasn't decided what tiles yet but I don't think they will be particulary heavy tiles. If they do happen to be too heavy for plaster, will I have to hack off all the plaster and put a strongish mortar skim on the walls?

Thanks again
Jim

 

[Maxsys]

You cannot (well you can but its a real pain in the ass) skim aquapanel, i would make sure you are only skimming onto PB, as for the skimmed wall, if you do need to hack it off what is underneath now? Just brick, block or render already?

 

[JimLoskot]

well its a victorian house so presumably whatever they use to use for undercoat plaster

 

[Maxsys]

well its a victorian house so presumably whatever they use to use for undercoat plaster

Depending on the tile type, as said 20Kg Sq Mtr for skimmed wall, inc 4Kg for addy & grout, any more than that and it will all have to come off, be rendered and then you will have to leave for at least 28 days to dry out until you can tile onto it., or you could hack it off, dot and dab moisture resistant PB onto it and mechanically fix through the dabs.

For your information

Wall Substrates Maximum Weight of Tiling per m²
Gypsum Plaster 20Kg/m²
Gypsum Plasterboard Direct (without a plaster skim) 32Kg/m²
Lightweight Tilebacking Boards* Up to 40Kg/m². Dependant upon the type and thickness of the board.
Glass reinforced Cement Sheets Up to 50kg/m², Dependant upon the type and thickness of the board.
Gypsum Fibre boards Approximately 35- 40Kg/m²

 

[JimLoskot]

thanks for all your help and advice Maxsys

 

[Maxsys]

Welcome